bluuebunny/crossref_metadata_2025 huggingface dataset:
Paucicanthus vanelstigen. et sp. nov., an Early Devonian (Lochkovian) acanthodian that lacks paired fin-spines
Authors: Hanke Gavin F
Published: October 2002

The acanthodian Paucicanthus vanelsti gen. et sp. nov. is described from six body fossils from Lower Devonian (Lochkovian) rocks of the southern Mackenzie Mountains, Northwest Territories, Canada. This new species is unique among acanthodians in that it lacks both pectoral and pelvic fin-spines. In the absence of fin-spines, the leading edges of the pectoral and pelvic fins are reinforced by enlarged scales. The anatomy of the acanthodiform Traquairichthys pygmaeus is similar to P. vanelsti in that both lack pelvic fin-spines, although T. pygmaeus also lacks pelvic fins. Similarly, the acanthodian Yealepis douglasi lacks both paired and median fin-spines, and its anatomy resembles that of P. vanelsti based only on the loss of paired fin-spines. The lack of paired and (or) median fin-spines in these three taxa contrasts with the widely held view that acanthodian fins all were preceded by spines. The anatomy of P. vanelsti also is similar to that of the acanthodian Brochoadmones milesi in that both have a completely unossified endoskeleton, slightly elevated pectoral fins, and deep, compressed bodies. The median fin-spines of P. vanelsti have an anterior leading edge rib followed by a field of fine striations. This striated ornamentation coupled with few leading edge ribs also is seen on fin-spines of Cassidiceps vermiculatus and primitive acanthodiform acanthodians (e.g., Mesacanthus and Lodeacanthus species). I tentatively suggest that this fin-spine ornament indicates relationship between P. vanelsti, acanthodiform acanthodians, and C. vermiculatus. However, a cladistic analysis is required to test whether or not the characteristics such as fin-spine loss, unossified endoskeleton, elevated pectoral fins, deep compressed bodies, and (or) median fin-spine ornamentation are synapomorphies within the Acanthodii or evolved convergently within the class.
Among- and within-species variability in fatty acid signatures of marine fish and invertebrates on the Scotian Shelf, Georges Bank, and southern Gulf of St. Lawrence
Authors: Budge Suzanne M , Iverson Sara J , Bowen W Don , Ackman Robert G
Published: October 2002

The fat and fatty acid compositions of 28 species of fish and invertebrates (n = 954) from the Scotian Shelf, Georges Bank, and the Gulf of St. Lawrence were determined. Discriminant analysis of the 16 most numerous species (n [Formula: see text] 18 each), using 17 major fatty acids, classified species with greater than 98% accuracy and grouped species into three general clusters (gadids, flatfish, and planktivores) with similar fatty acid compositions, and likely, similar diets. A number of species exhibited changes in fatty acid signatures with increasing size (multivariate analysis of variance), which corresponded with known dietary shifts reported from stomach contents analyses. Location effects were also observed among the three major geographical regions and were probably due to broad-scale variations in prey assemblages and phytoplankton composition in the northwestern Atlantic. Despite these effects, within-species variation was still substantially less than among-species variation. Thus, fatty acid signatures can be used to distinguish and characterize fish and invertebrate species in a given ecosystem, as well as to study finer-scale trophic interactions of these species. These data also have applications at higher trophic levels and will serve as a prey database for studying the diets of other fish and marine mammal predators using fatty acid signatures.
Sampling variability and the design of bacterial abundance and production studies in aquatic environments
Authors: Carr Geneviève M , Morin Antoine
Published: October 2002

Published data for aquatic bacterial abundance and production in benthic and planktonic environments were collected from the literature to describe relationships between sample means and variances, to explore the factors that affect these relationships, and to estimate the number of samples needed to detect specified differences among means with adequate power. Between 75 and 94% of sample log10(variance) was explained by log10(mean) for both bacterial abundance and production. Differences in mean-variance relationships of bacterial abundance and production due to habitat (river, lake, marine), quantification method, and experimental manipulation (planktonic bacteria) or substrate type (benthic bacteria) were negligible (less than 11% of residual variance from regressions explained). Between 12 and 69 replicates are necessary to detect a 20% difference in means for bacterial abundance and production with a power of 80%. Given the median rate of replication of 3 to 4, the majority of published studies reviewed here are, at best, able to detect differences in means of 50% (planktonic bacterial abundance) or 100% (planktonic production and benthic abundance and production) with 80% power. If effect sizes less than these values are deemed biologically meaningful, then future studies will have to increase sampling effort to enable detection of such differences.
Application de la méthode photonique à la détermination des paramètres physiques d'une cellule solaire monocristalline
Authors: Amar M Ben , Arab A Ben
Published: October 2002

The photonic's method is used in the study of monocristalline silicon solar cell (N+P). The induced photocurrent in the cell is analyzed with respect to the technological parameters such as the optical absorption coefficient of silicon and the emitter and base thickness. The spatial and frequential variations of the photocurrent of the cell, when the latter is illuminated by a sinusoidal modulated light, allow access to the diffusion length and lifetime of the minority carriers generated in a given region of the cell. In this paper, the physical parameters related to the base region are determined. In addition, this access is shown to be possible only when the total photocurrent of the cell is reduced to the base diffusion photocurrent.
Measurement of radiative lifetimes in Pr II and Nd II
Authors: Scholl T J , Holt R A , Masterman D , Rivest R C , Rosner S D , Sharikova A
Published: October 2002

We have measured the radiative lifetimes of 33 levels of Pr II and 13 levels of Nd II using two variants of the beam-laser method. The levels studied had term energies up to ~30 000 cm1 and lifetimes in the range 6170 ns. Experimental accuracy was in the range 111%. We have used these lifetimes to update transition probabilities for 82 transitions in Pr II in the wavelength range 392640 nm, which are useful for stellar abundance determinations.

PACS Nos.: 32.70Cs, 95.30Ky
Topology of QCD vacuum and color confinement
Authors: Chandola H C , Pandey H C , Nandan H
Published: October 2002

Using the magnetic symmetry structure of non-Abelian gauge theories of the YangMills type, the mathematical foundation of dual chromodynamics in fiber-bundle form is discussed. The dual gauge potential in its restricted form is constructed in terms of magnetic vectors on global sections, which has been shown to lead the dual dynamics between topological charges and color isocharges. Constructing the Lagrangian for such dual theory, the dynamical breaking of magnetic symmetry by an effective potential is shown to push the QCD vacuum in a confining phase. The dynamical structure of the theory is investigated by deriving the field equations associated with the confining phase. The associated flux-tube structure responsible for the confinement is analyzed by computing the asymptotic string solutions of the field equations under cylindrical symmetry. Using the confining part of the dual restricted Lagrangian, the finite string energy per unit length is calculated and its implications on color confinement are discussed.

PACS Nos.: 11.38Aw, 14.80Hv, 11.30Jw
In search of the enhanced value of the CP-violating ratio ε′ / ε
Authors: Bhattacharya A , Banerjee S N , Chakrabarti B , Banerjee S
Published: October 2002

The CP-violating ratio ε′ / ε and the top-quark mass are estimated using the value of | vub / vcb | extracted in the framework of the AltarelliCabbiboCorboMaianiMartinelli model along with the statistical model. It has been suggested that CabbiboKobyaschiMasakawa matrix elements play an important role in determining the value of ε′ / ε; the enhanced value of ε′ / ε can be obtained without lowering the strange-quark mass. The dependence of this important ratio on other parameters is also discussed with interesting conclusions. PACS Nos.: 12.30, 13.00, 12.20
Expanding the role of computers in physics education: a computer-based first-year course on computational physics and data analysis
Authors: de Bruyn J R , Lewis J KC , Morrow M R , Norris S P , Rich N H , Whitehead J P , Whitmore M D
Published: October 2002

We describe the design and implementation of a new first-year physics course introduced at Memorial University. This course makes extensive use of computers for the collection and analysis of experimental data and for modeling of physical phenomena. Major goals of the course are to educate students in the use of computers as a tool for doing science, to emphasize the interplay between theory and experiment in physics, and to enhance the students' learning of physics through inquiry-based and collaborative learning. Some preliminary results as to the effectiveness of the course in meeting these goals are presented. PACS Nos.: 01.50.Ht, 01.40.Di, 01.50.Lc
Water content - void ratio swell-shrink paths of compacted expansive soils
Authors: Tripathy S , Rao KS Subba , Fredlund D G
Published: October 2002

This paper addresses the behaviour of compacted expansive soils under swellshrink cycles. Laboratory cyclic swellshrink tests were conducted on compacted specimens of two expansive soils at surcharge pressures of 6.25, 50.00, and 100.00 kPa. The void ratio and water content of the specimens at several intermediate stages during swelling until the end of swelling and during shrinkage until the end of shrinkage were determined to trace the water content versus void ratio paths with an increasing number of swellshrink cycles. The test results showed that the swellshrink path was reversible once the soil reached an equilibrium stage where the vertical deformations during swelling and shrinkage were the same. This usually occurred after about four swellshrink cycles. The swelling and shrinkage path of each specimen subjected to full swelling  full shrinkage cycles showed an S-shaped curve (two curvilinear portions and a linear portion). However, the swelling and shrinkage path occurred as a part of the S-shaped curve, when the specimen was subjected to full swelling  partial shrinkage cycles. More than 80% of the total volumetric change and more than 50% of the total vertical deformation occurred in the central linear portion of the S-shaped curve. The volumetric change was essentially parallel to the saturation line within a degree of saturation range of 5080% for the equilibrium cycle. The primary value of the swellshrink path is to provide information regarding the void ratio change that would occur for a given change in water content for any possible swellshrink pattern. It is suggested that these swellshrink paths can be established with a limited number of tests in the laboratory.Key words: expansive soils, oedometer tests, swellshrink behaviour, shrinkage tests.
Effects of specimen consolidation on the laboratory hydraulic conductivity measurement
Authors: Kodikara J K , Rahman F
Published: October 2002

Laboratory hydraulic conductivity tests are commonly used for the design of clayey liners in waste containment. Although relatively small hydraulic gradients are encountered under field conditions, elevated gradients are desirable to reduce the testing time. It is generally believed, however, that these elevated gradients would reduce the conductivity measured owing to specimen consolidation. In the current paper a theoretical analysis is presented for assessing the effect of specimen consolidation. The theoretical results were compared with experimental results obtained for two local soils. Parametric analyses and nondimensional analyses were carried out and the results are presented. It was found that the hydraulic conductivity is dependent on the type of permeameter, the form of gradient application, and the state of stress within the soil. It was apparent that hydraulic conductivity can decrease with an increase in the hydraulic gradient, and the decrease was not significant up to a hydraulic gradient of about 300 for the soils tested.Key words: hydraulic conductivity, hydraulic gradient, specimen consolidation, volume change, permeameter.
Mechanical behavior of silty soils of the Venice lagoon as a function of their grading characteristics
Authors: Cola Simonetta , Simonini Paolo
Published: October 2002

The main feature of the shallowest quaternary basin of the well-renowned historic city of Venice, Italy and its surrounding lagoon, is the presence, apparently without any regular trend in depth and site, of a predominant silt fraction. This is always combined with clay and (or) sand, forming a chaotic and erratic interbedding of different sediments whose mineralogy is however variable in a relatively narrow range due to a unique geological origin and a common depositional environment. After a brief description of the basic soil indexes of the Venice lagoon soil, the present study, based on a comprehensive geotechnical laboratory investigation, describes the range of variation of the most relevant time-independent geotechnical properties. Moreover, a new grain size index, combining the geometrical characteristics of the particle distribution, is introduced. It is shown that the soil response at large and very small strains can be related to this grain size index, which appears to be able to include the influence of the soil grading on the description of the overall mechanical behavior.Key words: silt, mechanical behavior, Venice soil, grain-size index, laboratory investigation, critical state parameters.
Analysis of total DNA by minisatellite and simple-sequence repeat primers for the use of population studies inPlasmopara halstedii
Authors: Intelmann Frederik , Spring Otmar
Published: October 2002

Total DNA of Plasmopara halstedii isolates from Germany was analysed for polymorphisms potentially useful for the differentiation of field isolates with respect to epidemiological studies or pathotype characterization. The isolation of the DNA started from mitotically formed zoosporangia, which is the only cellular structure of the biotrophic pathogen accessible independently from its host. The total DNA of the pathogen was used to perform DNA fingerprints with minisatellite and simple-sequence repeat primers. Polymorphisms were found that allowed differentiation on the level of single field isolates; however, they were not correlated with either physiological races or the geographic origin of the isolates. Using such differentiating primers, single spore strains of three pathogen isolates were also analysed with respect to genetic homogeneity. Minor variation was visible in the mitotically derived offspring, but the overall appearance of these patterns was mostly uniform with those of the respective parental isolate.Key words: Plasmopara halstedii, polymerase chain reaction (PCR), simple sequences, mitochondrial DNA, Helianthus annuus.
The evaluation of mixtures of yeast and potato extracts in growth media for biomass production of lactic cultures
Authors: Gaudreau H , Renard N , Champagne C P , Horn D Van
Published: October 2002

The effectiveness of yeast extracts (YE) and potato extracts (PE) to promote growth of seven lactic cultures was evaluated by automated spectrophotometry (AS). Two aspects of the growth curve were analysed: (1) maximum biomass obtained (using ODmax) and (2) highest specific growth rate (μmax). Eleven lots from the same PE-manufacturing process were examined for lot-to-lot variability. The ODmaxvalues of three of the seven strains were significantly affected by lot source, but μmaxwas not significantly affected. The growth of bacteria was systematically lower in base medium containing 100% PE than in base medium containing 100% YE for both ODmaxor μmaxdata, which could be related to the lower content in nitrogen-based compounds in PE. In AS assays, highest OD values for Lactobacillus casei EQ28, Lactobacillus rhamnosus R-011, Lactobacillus plantarum EQ12, and Streptococcus thermophilus R-083 were obtained with a mixture of PE and YE. Fermentations (2 L) were also carried out to determine the accuracy of AS to predict biomass levels obtained under fermentation trials. In these fermentations, replacement of 50% YE with PE was shown to enable good growth of S. thermophilus. With L. rhamnosus R-011, a high correlation (R2= 0.95) was found between ODmaxdata obtained in the AS assays and that of the 2-L bioreactor when the same growth medium was used for both series of fermentations. However, AS was not as efficient when industrial media were used for the bioreactor assays. The relationship was still good for ODmaxbetween AS data and that of the bioreactor data with L. rhamnosus R-011 in industrial LBS medium (R2= 0.87), but was very poor with the S. thermophilus R-083 on Rosell #43 industrial medium (R2= 0.33). Since PE cost 40% less than YE, there are strong economic advantages in considering such a partial replacement of YE by PE. Key words: yeast extracts, potato extracts, lactic acid bacteria.
Molecular characterization of bacterial diversity from British Columbia forest soils subjected to disturbance
Authors: Axelrood Paige E , Chow Monica L , Radomski Christopher C , McDermott Joseph M , Davies Julian
Published: October 2002

Bacteria from forest soils were characterized by DNA sequence analysis of cloned 16S rRNA gene fragments (16S clones). Surface organic matter and mineral soil samples from a British Columbia Ministry of Forests Long-Term Soil Productivity (LTSP) installation were collected during winter and summer from two disturbance treatments: whole-tree harvesting with no soil compaction (plot N) and whole-tree harvesting plus complete surface organic matter removal with heavy soil compaction (plot S). Phylogenetic analyses revealed that 87% of 580 16S clones were classified as Proteobacteria, Actinobacteria, Acidobacterium, Verrucomicrobia, Bacillus/Clostridium group, Cytophaga-Flexibacter-Bacteroides group, green nonsulfur bacteria, Planctomyces, and candidate divisions TM6 and OP10. Seventy-five 16S clones could not be classified into known bacterial divisions, and five 16S clones were related to chloroplast DNA. Members of Proteobacteria represented 46% of the clone library. A higher proportion of 16S clones affiliated with γ-Proteobacteria were from plot N compared with plot S. 16S rRNA gene fragments amplified with Pseudomonas-specific primers and cloned (Ps clones) were examined from mineral-soil samples from plots N and S from three LTSP installations. A significantly greater proportion of sequenced Ps clones from plot N contained Pseudomonas 16S rRNA gene fragments compared with Ps clones from plot S.Key words: bacterial diversity, 16S rRNA gene, forest soil.
Western white pine development in relation to biophysical characteristics across different spatial scales in the Coeur d'Alene River basin in northern Idaho, U.S.A.
Authors: Jain Theresa B , Graham Russell T , Morgan Penelope
Published: October 2002

Many studies have assessed tree development beneath canopies in forest ecosystems, but results are seldom placed within the context of broad-scale biophysical factors. Mapped landscape characteristics for three watersheds, located within the Coeur d'Alene River basin in northern Idaho, were integrated to create a spatial hierarchy reflecting biophysical factors that influence western white pine (Pinus monticola Dougl. ex D. Don) development under a range of canopy openings. The hierarchy included canopy opening, landtype, geological feature, and weathering. Interactions and individual-scale contributions were identified using stepwise loglinear regression. The resulting models explained 68% of the variation for estimating western white pine basal diameter and 64% for estimating height. Interactions among spatial scales explained up to 13% of this variation and better described vegetation response than any single spatial scale. A hierarchical approach based on biophysical attributes is an excellent method for studying plant and environment interactions.
Response of the natural abundance of15N in forest soils and foliage to high nitrate loss following clear-cutting
Authors: Pardo L H , Hemond H F , Montoya J P , Fahey T J , Siccama T G
Published: October 2002

Export of microbially produced nitrate from an ecosystem is expected to increase δ15N in the remaining soil organic matter and NH4+. To test the hypothesis that nitrification and nitrate loss induced by clear-cutting cause an increase in soil and foliar δ15N, we measured δ15N in a clear-cut watershed at the Hubbard Brook Experimental Forest, New Hampshire. δ15N ranged from 0.02 in the Oie horizon to 7.7 in the Bs2 horizon prior to clear-cutting and increased significantly by 1.3 in the Oie horizon and 0.9 in the Oa horizon 3 years after clear-cutting. Fifteen years after clear-cutting, δ15N in both O horizons decreased to near-initial values. No significant temporal changes in the Bs2 and C horizons δ15N were observed. Foliar δ15N was highest (1.7) the first 2 years after clear-cutting and was significantly higher than in the reference watershed (mean δ15N = 1.2), decreasing to 0.0 35 years after clear-cutting and to 1.3 911 years after clear-cutting. Increased foliar δ15N coincided with increased stream-water nitrate concentration, suggesting that the increased nitrification responsible for elevated stream-water nitrate may also have caused an enrichment of the plant-available ammonium pool. The response observed in this catchment also suggests that sampling of soil or foliar δ15N may provide a practical alternative to long time series of stream chemistry for evaluating nitrogen saturation of forested ecosystems.
NOTEAging discrepancies of white spruce affect the interpretation of static age structure in boreal mixedwoods
Authors: Peters Vernon S , Macdonald S Ellen , Dale Mark RT
Published: October 2002

Post-fire regeneration of Picea glauca (Moench) Voss on boreal mixedwood sites appears to be highly variable over time. Our objectives were to determine whether ground-level ring counts underestimate root collar age of understory P. glauca and whether aging errors increase with stand age. Trees were collected from one to nine stands in each of three fires occurring in mast years between 1961 and 1991. Trees were cut at ground level (humus soil level), and the belowground stumps were excavated, sectioned, and internally cross-dated with skeleton plots after identifying the root-collar location. Ground-level disks were visually cross-dated with a master chronology, which was constructed using the dendrochronology program COFECHA. Ground-level ring counts underestimated age by a mean of 2.4 years (range 06) and 6.4 years (range 013) in 20- and 38-year-old stands, respectively. Age underestimation was significantly greater at the root collar than ground level because of missing rings. Cross-dated age structures showed that apparent regeneration lags in 20- and 38-year-old stands were artifacts of ground-level ring counts and that the first year post-fire was the most important establishment year in all mast year burns. We conclude that aging errors have led to inaccurate depictions of regeneration patterns during early mixedwood stand development. Our results portray a different picture of P. glauca succession and have important implications for forest management.
Increased boron concentrations of Scots pine foliage induced by green pruning
Authors: Nuorteva Heikki
Published: October 2002

The responses of Scots pine (Pinus sylvestris L.) foliar boron (B) concentrations to artificial defoliation by green pruning were studied by examining sample trees for 3 years after the treatments. In winter, concentrations of boron in foliage were determined individually from needles on the lateral top shoots of 168 sample trees (at the beginning 28 m, at the end 410 m tall). To prevent the pruning residues from affecting the nutrition of the sample trees, all pruned branches were transported away from the research area. Before pruning, there were no differences in foliar B among the pruning classes. Reduction of the living crown by pruning (LCRP, % of the initial crown ratio) 50% or more increased the concentrations of foliar B drastically for 3 years. The increase was greatest in the largest trees with the highest LCRP (about 70%), where the mean concentrations of foliar B one year after pruning were nearly 180% higher than in the unpruned trees. Pruning of the dead branch whorls or only the few lowest living whorls did not affect the boron nutrition of the trees. In the current study, the ability of rapid and sufficiently large defoliation to increase B concentrations for several years in the Scots pine foliage was confirmed experimentally; earlier suggestions have been based on analyses made after defoliation. The potential suitability of green pruning is discussed as a method for improving the boron status of trees in boron-deficient areas.
OPERATORS ON MODULI FOR SPHERICAL MAPS OF HOMOGENEOUS SPACES
Authors: TOTH GABOR
Published: October 2002

The DoCarmo–Wallach theory studies isometric minimal immersions f : M → Sn of a compact Riemannian homogeneous space M = G/K into Euclidean n-spheres. The parameter space of such immersions is a compact convex body in a representation space for the Lie group G. In this article we give a very general definition of the moduli space and study its geometric properties such as the distortion (as a convex set). In addition, we introduce a general notion of operators, derive various criteria under which they map the moduli into one another, and finally, we show that, under general conditions, the operators are distortion decreasing.
GLOBAL ZETA FUNCTIONS OF FREUDENTHAL QUARTICS
Authors: SAITO HIROSHI
Published: October 2002

We give two applications of an explicit formula for global zeta functions of prehomogeneous vector spaces in Math. Ann.315 (1999), 587–615. One is concerned with an explicit form of global zeta functions associated with Freudenthal quartics, and the other the comparison of the zeta function of a unsaturated prehomogeneous vector space with that of the saturated one obtained from it.
QUANTUM MARKOV PROCESSES (CORRESPONDENCES AND DILATIONS)
Authors: MUHLY PAUL S. , SOLEL BARUCH
Published: October 2002

We study the structure of quantum Markov Processes from the point of view of product systems and their representations.
A COMPLETE SET OF ISOMETRIC IMPLEMENTERS FOR A QUASI-FREE ENDOMORPHISM OF THE CAR ALGEBRA VIA UNITARY DILATIONS
Authors: GABRIEL MICHAEL J.
Published: October 2002

In this paper we concern ourselves with non-surjective quasi-free endomorphisms of the CAR algebra. More precisely we give a construction of a complete set of isometric implementers for such an endomorphism in a fixed pure quasi-free state, the approach to which is more natural than has previously been proposed. The key idea in this construction is the use of the unitary implementers of an associated quasi-free automorphism in a set of carefully chosen quasi-free states. Our treatment is also novel in that we provide a sequence of implementers within the framework of the complex formalism of the CAR algebra.
COMMENT ON "EVIDENCE FOR NEUTRINOLESS DOUBLE BETA DECAY"
Authors: AALSETH C. E. , AVIGNONE F. T. , BARABASH A. , BOEHM F. , BRODZINSKI R. L. , COLLAR J. I. , DOE P. J. , EJIRI H. , ELLIOTT S. R. , FIORINI E. , GAITSKELL R. J , GRATTA G. , HAZAMA R. , KAZKAZ K. , KING G. S. , KOUZES R. T. , MILEY H. S. , MOE M. K. , MORALES A. , MORALES J. , PIEPKE A. , ROBERTSON R. G. H. , TORNOW W. , VOGEL P. , WARNER R. A. , WILKERSON J. F.
Published: October 2002

We comment on the recent claim for the experimental observation of neutrinoless double-beta decay. We discuss several limitations in the analysis provided in that paper and conclude that there is no basis for the presented claim.
THE ROLE OF SELF-COUPLINGS OF SCALAR MESONS IN NEUTRON STAR MATTER
Authors: POCHA S. S. , TAURINES A. R. , VASCONCELLOS C. A. Z. , PINTO M. B. , DILLIG M.
Published: October 2002

The influence of nonlinear cubic and quartic self-couplings of the scalar meson field in nuclear matter is investigated. In summing the leading tadpole corrections for the Dirac-vacuum, we compare two approaches, the modified relativistic Hartree approximation, applied to the Walecka model, and the relativistic Hartree approximation, employed to the nonlinear model, respectively. These two approaches render similar expressions for the equation of state of nuclear matter up to the fifth order in the scalar meson field. We find that, by exploring the parameter dependence of the two models, they yield similar results for the bulk static properties of nuclear matter. However, increasing the baryon density the two models start to deviate significantly, such as in the predictions for the maximal mass of a neutron star or in the role of hyperon degrees of freedom in dense matter. The results indicate that with increasing density, scalar meson self-couplings beyond the fourth order seem to play a significant role.
A MINI-REVIEW OF CONSTRAINTS ON EXTRA DIMENSIONS
Authors: UEHARA YOSUKE
Published: October 2002

We present a mini-review of the present constraints of the large extra dimension scenario. We show many experiments and considerations that can constrain the fundamental scale of the large extra dimension. We observe that constraints come from collider experiments are much weaker than those of astrophysical and cosmological considerations. When the number of extra dimension n is smaller than four, the constraint is so strong that the large extra dimension scenario cannot solve hierarchy problem. But when n ≥ 4 there is still possibility that it can solve the hierarchy problem.
HAMILTONIAN STRUCTURES FOR THE NONREGULAR CONSTRAINED FLOWS OF THE AKNS HIERARCHY
Authors: SIRENDAOREJI  , JIONG SUN
Published: October 2002

The Hamiltonian structures of the first two nonregular constrained flows of the AKNS hierarchy are constructed by modifying the Jacobi–Ostrogradsky coordinates. The nonregular constrained flows are also proved to be completely integrable in the Liouville's sense.
NONLEPTONIC KAON DECAYS: THEORY VS. EXPERIMENT
Authors: CHESHKOV C.
Published: October 2002

A review of the present experimental status of the rates and the Dalitz-plot slope parameters in CP conserving K→2π and K→3π decays is given. The corresponding isospin amplitudes have been determined by a common fit to the recent experimental data and have been used as an input to a consequent fit based on the constraints from O(p4) chiral Lagrangian. It has been found that the constraints of the chiral fit are well satisfied by the experimental data, allowing one to estimate the weak coupling constants and to predict the quadratic amplitudes in K→3π decays and the one-loop strong rescattering phases. The consistency of the obtained weak coupling constants with weak resonance models has also been considered.
CONSTRAINED HAMILTONIANS AND LOCAL-SQUARE-ROOT ACTIONS
Authors: MURCHADHA NIALL Ó.
Published: October 2002

The configuration space of general relativity is superspace, the space of Riemannian three-geometries and the Hamiltonian is just a sum of constraints, with Lagrange multipliers. One can go from this Hamiltonian, via a Legandre transformation, back and forth to the Lagrangian. The Lagrange multiplier (the lapse function) can be eliminated from the Lagrangian and one is left with an action which is a product of square roots. This is the Baierlein-Sharp-Wheeler action for general relativity. This action is unique in that all other square root actions are not self-consistent. This paper shows how to express this result in phase space. The only selfconsistent constrained Hamiltonian on superspace which is ultralocal and quadratic in the momenta in the ADM Hamiltonian for general relativity.
SIMULATED GRAVITY IN ASYMMETRIC BRANEWORLD SCENARIOS
Authors: UZAN JEAN-PHILIPPE
Published: October 2002

I review the main aspects of the simulated gravity that arises in brane world models in which the reflection symmetry is broken.
CAUSAL TENSORS AND SIMPLE FORMS
Authors: BERGQVIST G.
Published: October 2002

A rank-r tensor on a Lorentzian manifold of dimension N is causal if the contraction with r arbitrary causal future-directed vectors is non-negative. General superenergy tensors1, such as the Bel and Bel-Robinson tensors, are examples of even ranked causal tensors1,2, and may therefore be useful when defining norms for geometric evolution equations3. We here show that any symmetric rank-2 causal tensor (energy-momentum tensors satisfying the dominant energy condition) can be written as a sum of at most N superenergy tensors of simple forms. If N=4 this can be expressed in an elegant way as the sum of four spinors squared. Since, for arbitrary N, the superenergy of any simple form is a self-map of the cone (its square is proportional to the metric) this leads to new representations and classifications of all conformal Lorentz transformations and to generalisations of the classical four dimensional Rainich-Misner-Wheeler (RMW) theory of determining the space-time physics from its geometry4. For non-simple forms more complicated equations are satisfied by the superenergy tensors, but also in this case we are able to generalise the RMW theory, and as an example the complete algebraic RMW theory in five dimensions is obtained5.
QUASI-NORMAL MODES OF SCHWARZSCHILD–ANTI-DE SITTER BLACK HOLES: ELECTROMAGNETIC AND GRAVITATIONAL PERTURBATIONS
Authors: CARDOSO VITOR , LEMOS JOSÉ P. S.
Published: October 2002

We studied the quasi-normal modes (QNM) of electromagnetic and gravitational perturbations of a Schwarzschild black hole in an asymptotically anti-de Sitter (AdS) spacetime, extending previous works1,2 on the subject. Some of the electromagnetic modes do not oscillate, they only decay, since they have pure imaginary frequencies. The gravitational modes show peculiar features: the odd and even gravitational perturbations no longer have the same characteristic quasinormal frequencies. There is a special mode for odd perturbations whose behavior differs completely from the usual one in scalar1 and electromagnetic perturbation in an AdS spacetime, but has a similar behavior to the Schwarzschild black hole3 in an asymptotically flat spacetime: the imaginary part of the frequency goes as [Formula: see text], where r+ is the horizon radius. We also investigated the small black hole limit showing that the imaginary part of the frequency goes as [Formula: see text]. These results are important to the AdS/CFT4 conjecture since according to it the QNMs describe the approach to equilibrium in the conformal field theory. For other geometries see5,6.
ASSISTED INFLATION
Authors: COLEY A. A. , VAN DEN HOOGEN R. J.
Published: October 2002

The dynamical properties of spatially homogeneous and isotropic cosmological models containing a barotropic perfect fluid and multiple scalar fields with independent exponential potentials is investigated. It is shown that the assisted inflationary scaling solution is the global late-time attractor for the parameter values for which the model is inflationary, even when curvature and barotropic matter are included. For all other parameter values the multi-field curvature scaling solution is the global late-time attractor (in these solutions the curvature is not dynamically negligible asymptotically). Consequently, in general all of the scalar fields in multi-field models with exponential potentials are non-negligible in late-time behaviour, contrary to what is commonly believed.
NON-MINIMAL COUPLING, VARIABLE SPEED OF LIGHT AND COSMOLOGY
Authors: TEYSSANDIER P.
Published: October 2002

Presently, there exists some renewed interest in time varying speed of light theories as possible solutions of the major cosmological problems1. It is often believed that the local Lorentzian invariance is broken if the speed of light in a vacuum is not a constant. We point out that this belief is not necessarily founded and that a variable speed of light is perfectly consistent with general relativity under the assumption of non-minimal coupling between electromagnetism and curvature. Two kinds of arguments may be invoked in favour of such an assumption. First, a theorem due to Horndeski2shows that in a four-dimensional space-time the Einstein-Maxwell field equations are not the only second-order vector potential field equations which stem from a Lagrangian scalar density, are consistent with the charge conservation and reduce to Maxwell's equations in a flat space-time (see also3). Second, according to QED4,5, vacuum polarization induces tidal gravitational effects which imply that photons propagating in a curved space-time have velocities exceeding the value of the "Lorentzian structural constant" c. The modified electromagnetic field equations given by Horndeski2are studied here in the geometrical optics limit. Considering the case of Friedmann-Robertson-Walker cosmological models, we find the value of the speed of light as a function of the energetic content of the universe. We deduce from this result a new equation of state for a photon gas and we discuss the consequences of this equation on the evolution of the scale factor during the radiation-dominated era.
Quarkonia Production at CDF
Authors: Papadimitriou Vaia
Published: October 2002

In this paper we present results on J/ψ, ψ(2S), χc and ϒ production at [Formula: see text]. These results were obtained from data taken with the CDF detector at Fermilab. We cover recently completed analyses of the 1992-95 collider run. We find an excess of J/ψ, ψ(2S) and ϒ production compared with the predictions from the Color Singlet Model. Prospects for the near future are also discussed.
Quarkonium Polarization in the NRQCD Factorization Framework
Authors: Braaten Eric
Published: October 2002

The NRQCD factorization approach for calculating inclusive production of heavy quarkonium gives unambiguous predictions for the polarization of quarkonium states. The factorization formula for polarized states can be obtained by using the threshold expansion method to calculate the short-distance coefficients and then using symmetries of NRQD to reduce the NRQCD matrix elements. A particularly dramatic prediction of the NRQCD factorization framework is that prompt psi's and psi-primes's produced at the Tevatron should be predominantly transversely polarized at large transverse momentum.
Puzzles in Hadronic Charmonium Decays
Authors: Olsen Stephen L.
Published: October 2002

Recent results of experimental studies of hadronic decays of charmonium states using the BES detector are reported. A number of puzzling features are observed. Foremost among these is the large discrepancy between the decay rates for J/ψ and ψ(2S) decays to ρπ and [Formula: see text] final states, first observed by the Mark II experiment. We find suppressions for ψ(2S) decays to these modes of factors in excess of sixty and twenty, respectively. Similar, although less dramatic, suppressions of vector plus tensor meson final states are also observed. No suppression is seen for axialvector plus pseudoscalar meson decays, but a strong flavor-SU(3) violation is seen in [Formula: see text] final states that has an opposite character for the J/ψ and ψ(2S).
Confinement and Spin
Authors: Olsson M. G.
Published: October 2002

The experimental and theoretical evidence relating spin dependence and long range confinement is reviewed. One of the simplest confinement ideas, the dynamic electric flux tube picture of Buchmüller, can be exploited to yield a complete effective Hamiltonian. In addition to pure Thomas spin-orbit splitting the other relativistic corrections are calculated. It is shown that our effective Hamiltonian is identical to the mechanical relativistic flux tube model and gives relativistic corrections in agreement with QCD predictions.
EPR AND MAGNETIC SUSCEPTIBILITY STUDIES OF V4+ IONS IN 2B2O3·SrO GLASS MATRIX
Authors: ARDELEAN I. , COZAR O. , CRACIUN C. , CEFAN C.
Published: October 2002

Electron paramagnetic resonance (EPR) and magnetic susceptibility studies on x V 2 O 5 ·(100 - x)[2 B 2 O 3 · SrO ] glasses with 0 ≤ x ≤ 30 mol% were performed. The covalence degree of vanadium bonds was estimated according to the LCAO-MO model. The EPR data show the presence of V4+ ions in a square-pyramidal coordination (C4v). The experimental EPR spectra are simulated assuming a superposition of two signals, one with hyperfine structure (HFS) typical for isolated ions and the other one consists of a broad line without HFS characteristic for clustered ions. These results are consistent with the magnetic data which indicate that for x ≥ 5 mol% V2O5 the temperature dependence of the reciprocal magnetic susceptibility is described by a Curie–Weiss type law with negative paramagnetic Curie temperature. The magnetic data also allow the estimation of NV4+ / Ntotal ratio.
IR STRUCTURAL INVESTIGATION OF THE xFe2O3 · (100 - x) [3B2O3 · KCl] GLASS SYSTEM
Authors: ARDELEAN I. , PĂŞCUŢĂ P.
Published: October 2002

Samples belonging to the x Fe 2 O 3 · (100 - x) [3 B 2 O 3 · KCl ] glass system with 0 ≤ x ≤ 20 mol% were investigated by IR spectroscopy in order to obtain information about the influence of Fe 2 O 3 on the local order in the 3B 2 O 3 · KCl glass matrix. The interpretation of the obtained vibrational spectra revealed the presence and the dependence of the local structural units in glasses studied by the Fe 2 O 3 content.
LINEAR Bi-CMOS TRANSCONDUCTANCE FOR Gm-C FILTER APPLICATIONS
Authors: LEE J. , HAYATLEH K. , LIDGEY F. J. , DREW J.
Published: October 2002

In this paper a novel transconductance Bi-CMOS stage is described. This stage makes combined use of a translinear current gain cell and a negative resistance cell, to generate a linear tuneable transconductor. The transconductance stage was designed specifically for an integrated Gm-C filter application, and is shown to perform well at high frequencies.
INDUCTANCE EFFECTS IN RLC TREES
Authors: ISMAIL YEHEA I. , FRIEDMAN EBY G. , NEVES JOSE L.
Published: October 2002

A closed form solution for characterizing voltage-based signals in an RLC tree is presented. The closed form solution is used to derive figures of merit to characterize the effects of inductance at a specific node in an RLC tree. The effective damping factor of the signal at a specific node in an RLC tree is shown to be one useful figure of merit. It is shown that as the effective damping factor of a signal increases, an RC model is sufficiently accurate to characterize the waveform. The rise time of the input signal driving an RLC tree is shown to be a second factor that affects the relative significance of inductance. As the rise time of the input signal increases as compared to the effective LC time constant at a specific node within an RLC tree, the signal at this node will no longer exhibit the effects of inductance. It is demonstrated that a single line analysis to determine the importance of including inductance to characterize an interconnect line that is a part of a tree is invalid in many cases and can lead to erroneous conclusions. The error exhibited by single line analysis is due to the large interaction among the branches of the tree.
COMPLEX DYNAMICS IN A SIMPLE STOCK MARKET MODEL
Authors: ALVAREZ-RAMIREZ JOSE , IBARRA-VALDEZ CARLOS , FERNANDEZ-ANAYA GUILLERMO
Published: October 2002

A deterministic model is introduced in terms of conservation principles to describe the (qualitative) price dynamics of a stock market. It is shown how the fundamentalist and chartist patterns of the trader behavior affect the price dynamics. The model can display complex oscillatory behavior with transient erratic oscillations, which resembles the behavior found in actual price dynamics. By means of numerical simulations, it is shown that the model can produce price time-series with statistics similar to that found in real financial data.
WAVES IN EXCITABLE MEDIA: EFFECTS OF WAVE GEOMETRY
Authors: WELLNER MARCEL , JALIFE JOSÉ , PERTSOV ARKADY M.
Published: October 2002

We consider waves in two-dimensional excitable media. The correct form of the eikonal equation (i.e. the formula that predicts propagation speed as a function of curvature) is a question that has surfaced and resurfaced during the last twenty years or so. Good answers have become available in limiting cases and under certain approximations, notably weak curvatures, low frequencies, and sharp wave fronts. The solution is important in some cardiac pathologies, as well as in our basic understanding of excitable-medium mathematics. After a brief review of curvature effects, particularly in heart tissue, we demonstrate how to obtain a drastically corrected formula that is free of restrictions on frequency and sharpness. (In the original limiting cases the result is unchanged.) Our derivation uses a finite-renormalization method. We illustrate the formula in the context of cardiac tissue. For the sake of definiteness we work in terms of FitzHugh–Nagumo-like models.
HOW ANTIARRHYTHMIC DRUGS INCREASE THE RATE OF SUDDEN CARDIAC DEATH
Authors: STARMER C. FRANK
Published: October 2002

Two large clinical trials of drugs that exhibited significant antiarrhythmic properties in single cells were found to increase the rate of sudden cardiac death in patients by two to three fold over untreated patients. We hypothesized that premature excitation within the drug-altered vulnerable region, a region that trails each excitation wave, might be one mechanism for initiating re-entrant tachyarrhythmias that could lead to ventricular fibrillation and sudden cardiac death. With numerical studies of a cardiac cell model, we probed the determinants of the vulnerable period. We found that antiarrhythmic drugs that block the sodium channel can increase the duration of the cardiac vulnerable period by both slowing conduction velocity and reducing the gradient of excitability. Coupling the dynamics of drug binding to ion channels with wave formation in a nonlinear excitable medium provides new insights into possible arrhythmogenic mechanisms.
SPATIO-TEMPORAL DYNAMICS OF BLOOD COAGULATION AND PATTERN FORMATION: AN EXPERIMENTAL STUDY
Authors: ATAULLAKHANOV F. I. , KRASOTKINA YU. V. , SARBASH V. I. , VOLKOVA R. I. , SINAURIDSE E. I. , KONDRATOVICH A. YU.
Published: October 2002

We examined the dynamics of clot growth in vitro and found, that initially the clot grows at a constant speed, then abruptly stops and becomes surrounded by an "inhibition zone" in which coagulation is strongly suppressed. We also observed formation of "stratified structures" (target patterns) in which solid layers alternate with liquid blood. The experimental results strongly support a hypothesis that blood is a new type of excitable medium.
SPATIO-TEMPORAL DYNAMICS OF BLOOD COAGULATION AND PATTERN FORMATION: A THEORETICAL APPROACH
Authors: ATAULLAKHANOV F. I. , ZARNITSINA V. I. , POKHILKO A. V. , LOBANOV A. I. , MOROZOVA O. L.
Published: October 2002

We constructed a mathematical model of clotting, which is based on a current view of the molecular pathways of blood coagulation. Several hypothetical reactions are introduced to allow accurate description of the spatio-temporal dynamics of blood clotting. The resulting model describes well all spatio-temporal aspects of clotting, as well as data obtained in the homogeneous systems.
FOLDING DYNAMICS IN A SEMIFLEXIBLE POLYMER AS A MODEL OF DNA
Authors: NOGUCHI HIROSHI
Published: October 2002

We studied the folding transition of a semiflexible homopolymer chain using a Brownian dynamics simulation. A duplex DNA chain exhibits a discrete transition between an elongated coil state and a folded state with toroidal morphology. We show that these folding properties are understood with the stiffness of DNA chains. Semiflexible chains fold through various paths into collapsed toroidal states stochastically. Some chains fold directly by winding around a ring along a chain. Others fold through rod states, which are kinetically trapped metastable states.