bluuebunny/crossref_metadata_2025 huggingface dataset:
Peptide Sequencing by Matrix-Assisted Laser Desorption/Ionisation and Post-Source Decay Mass Spectrometry: A Rapid Method to Design Oligonucleotide Hybridisation Probes for Cloning cDNA Encoding Pyranose 2-Oxidase from Trametes multicolor
Authors: Halada Petr , Leitner Christian , Volc Jindřich , Haltrich Dietmar , Havlíček Vladimír
Published: July 2002

A rapid and elegant method for designing oligonucleotide hybridisation probes for cloning cDNA encoding a biologically and/or biotechnologically important protein is presented. The approach is based on proteolytic digestion of a protein of interest and subsequent matrix/assisted laser desorption/ionisation mass spectrometric (MALDI-MS) analysis of the resulting peptide mixture. The method is demonstrated on the analysis of pyranose 2-oxidase (P2O), a homotetrameric flavoprotein used as a catalyst component in several biotechnologically important carbohydrate conversions. P2O from the fungusTrametes multicolorwas cleaved directly in the gel by two different proteases and the peptides formed were subjected to MALDI-MS. A comparison of the obtained peptide maps to those theoretically derived from the known sequence of homologous P2O (Trametes versicolor) allowed us to select peptide candidates for designing hybridisation probes. The suitable peptides were sequenced by post-source decay (PSD) analysis. The acquired sequence data are aimed at cloning and sequencing ofT. multicolor p2ocDNA and at production of the recombinant enzyme.
Hydration Analysis and the Expansion of Relative Activity Coefficients
Authors: Nývlt Jaroslav
Published: July 2002

Of correlation methods for solubility in ternary systems, the method of expansion of relative activity coefficients and the hydration analysis are based on the thermodynamic condition of phase equilibria. Both of them require only reliable solubility data in the ternary system and corresponding binary systems. Correlation parameters of both of these methods are interrelated and the methods are compared on the system K2SO4-H2SO4-H2O at 50 °C.
Formation of Infinite Grids with Chiral Square Compartments by Self-Assembly of Achiral 1,1'-Biphenyl-2,2',6,6'-tetracarboxylic Acids. Effect of 4,4'-Substitution on the Grid Stacking
Authors: Holý Petr , Závada Jiří , Zezula Josef , Císařová Ivana , Podlaha Jaroslav
Published: July 2002

The achiral 1,1'-biphenyl-2,2',6,6'-tetracarboxylic acid as well as its 4,4'-dibromo and 4,4'-dinitro derivative self-assemble in crystal under formation of a two-dimensional grid set up from hydrogen-bonded cyclotetrameric compartments which are individually chiral (D4 symmetry). The roughly square cavities (ca 5.6 Å) of individual compartments partly accommodate the perpendicularly oriented benzene rings of the neighbouring grid, in dependence on the nature of the 4,4'-substituents. As a consequence, the grids are stacked in a staggered (nonconcatenated) manner.
Charge Distribution Within 1,2-Dicarba-closo-dodecaborane: Dipole Moments of Its Phenyl Derivatives
Authors: Hnyk Drahomír , Všetečka Václav , Drož Ladislav , Exner Otto
Published: July 2002

The dipole moment of 1,2-dicarba-closo-dodecaborane is oriented with the positive end towards the carbon atoms as follows from measurements on phenyl derivatives with variable substituents. Towards the phenyl group, the substituent 1,2-C2B10H11 behaves as a weak electron acceptor.
Increased prevalence of impaired hearing in patients with type 2 diabetes in western India
Authors: Kashyap A S , Kashyap S
Published: July 2002

In an out-patient study of 1344 general medical patients over 50 years old in India, the prevalence of hearing aid use was found to be significantly greater in type 2 diabetics.
Diagnosis of malignant melanoma by general practitioners and hospital specialists
Authors: Jackson A M , Morgan D R , Ellison R
Published: July 2002

The aim of this study was to audit all malignant melanomas confirmed histologically in the Scarborough Health District over six years, prompted by the continuing rise in incidence rate nationally and relatively high number of malignant melanomas excised by general practitioners (GPs) in this area. A total of 157 malignant melanomas were diagnosed (60% from females and 40% from males) over the six years; primary excisions being carried out by GPs (37%) and hospital specialists (63%). The clinical diagnosis of malignant melanoma was made in 9% of GP cases and 35% of the hospital specialist cases. However another 45.5% of GP cases, and 38% of hospital specialist cases were regarded as suspicious pigmented lesions clinically. The histological diagnosis was of superficial spreading malignant melanoma in 72% of the GP and 69% of the hospital specialist cases. Most of the GP melanomas were excised with a lateral margin of 2 mm or less (71%); around half of the hospital excisions had a margin of over 2 mm (49%). Most melanomas were 2 mm or less in depth (Breslow depth) in both the GP (81%) and hospital specialist (75%) series. Over the six year period (1993–98) the incidence of malignant melanomas has continued to rise, but Breslow depth at diagnosis has not changed significantly. It is therefore important to continue with early recognition of this condition by GPs in the first instance, reduction in its incidence being the long term goal. During five years of the study there were only 67 lesions thought clinically to be malignant melanoma (26 GP and 41 hospital specialist cases), but which proved to be benign histologically.
Risperidone implicated in the onset of tardive dyskinesia in a young woman
Authors: Kumar Shailesh , Malone Darren M
Published: July 2002

The aim of this case report is to highlight that risperidone may cause and ameliorate tardive dyskinesia. A 16 year old white women with a 12 month history of schizophrenia, developed buccolingual masticatory tardive dyskinesia after receiving risperidone 6 mg. She had received small dosages of typical antipsychotics before and during receiving risperidone for short periods. Recommencement of risperidone with 2 mg and increasing to 6 mg resulted in improvement in tardive dyskinesia and up until now she remains free of any abnormal involuntary movements.
Role of carotid sinus syndrome and neurocardiogenic syncope in recurrent syncope and falls in patients referred to an outpatient clinic in a district general hospital
Authors: Eltrafi Abuzeid , King Debra , Silas Joseph H , Currie Peter , Lye Michael
Published: July 2002

Carotid sinus syndrome (CSS) and neurocardiogenic syncope (NCS) are recognised as important causes of recurrent syncope and falls in the elderly. In this study the role of CSS (diagnosed with carotid sinus massage) and NCS (diagnosed with prolonged head-up tilt) in a district general hospital were investigated.

Over 27 consecutive months carotid sinus massage was performed in 139 patients. Of these 29 (20.8%) patients (mean (SD) age of 78 (9) years) showed a positive response. Of these 18 (62%) patients showed a positive response only when carotid sinus massage was performed with 70° head-up tilt.

Thirteen (8.7%) of the 149 patients who had prolonged head-up tilt testing were found to have NCS. The mean (SD) age for patients with NCS was 59 (26) years and the mean (SD) time required to produce a positive response during prolonged head-up tilt was 12 (5) minutes.

It is concluded that carotid sinus massage and head-up tilt testing are useful in patients presenting with unexplained syncope and falls in a district general hospital setting. Carotid sinus massage should be repeated upon head-up tilt if a negative response is obtained in the supine position.
Are single mothers in Britain failing to monitor their oral health?
Authors: McGrath C , Yeung C Y Y J , Bedi R
Published: July 2002

Objectives

This study was designed to identify association between self reported dental attendance patterns and family structure in the UK.

Design

A national study involving 666 women with dependent children.

Setting

Home interviews were undertaken exploring time and reason for last dental visit. In addition, numerous sociodemographic and service related characteristics were collected.

Results

Bivariate analysis identified that family structure was associated with respondents’ self reported dental attendance patterns: marital status (p<0.01), number of children (p<0.05), and age of children (p<0.05). When the combined effects of age, family structure, income, educational attainment, working status, and service factors (difficulty obtaining a NHS dentist and time taken to get an appointment) on dental attendance were explored, family structure emerged as a very important predicator of service use. Notably, young (age 16–34) single mothers and those with more than two children were less likely to have attended the dentist within the past year for reasons other than a dental emergency compared with older (age 35 or more), mothers from a two parent family and those with one or two children.

Conclusion

Family structure is associated with self reported dental attendance patterns. Young single mothers with more than two children may be failing to monitor their oral health appropriately.
Analysis of interspecific variation in plant growth responses to nitrogen
Authors: Taub Daniel R
Published: July 2002

Plant species differ greatly in their growth responses to nutrients, but little is known about the physiological and morphological factors that are responsible for this variation. To address this question, I measured the responses to added nitrogen of relative growth rate and three of its components (specific leaf area, unit leaf rate, and leaf weight ratio) for 17 C3 grass species. Plants were grown in sand culture in a greenhouse and were fertilized daily with either 5 or 0.05 mM NH4NO3. For most species, growth response to nitrogen was primarily associated with an increased mass allocation to leaves at high versus low nitrogen. Across all species, the average response at high versus low nitrogen was a 37% increase in leaf weight ratio, a 12% increase in unit leaf rate, and a 4% decrease in specific leaf area. Interspecific differences in growth response to nitrogen, however, were associated primarily with species differences in the response of unit leaf area to nitrogen supply. I determined the nitrogen response ratio of each parameter as the value of the parameter at high nitrogen divided by the value at low nitrogen. The rank-order correlation between the unit leaf area response ratio and the relative growth rate response ratio was 0.88. Reanalysis of previous experiments on plant nutrient response showed a similar pattern. In all studies, interspecific variation in the response of relative growth rate to nutrients was associated primarily with interspecific differences in the plastic response of unit leaf area.Key words: leaf weight ratio, net assimilation rate, plant growth analysis, relative growth rate, specific leaf area, unit leaf rate.
Biologie de la reproduction de Aloe mayottensis (Liliaceae), une espèce endémique de l'île Mayotte (Océan Indien)
Authors: Pailler Thierry , Warren Benjamin , Labat Jean-Noël
Published: July 2002

A particularly interesting aspect of the study of organisms in insular environments is plant reproduction and the interaction of plants with their pollinators. Differences in composition between the fauna and flora of continental and island populations, combined with their geographical isolation, have frequently driven rapid evolution in colonizing populations. In particular, floral traits and compatibility systems tend to favour autogamy in response to a paucity of pollinators in the environment. In this context we investigate the origins of the reproductive biology of Aloe mayottensis Berger, a lily endemic to the island of Mayotte. We show that this species is pollinated by the island's endemic sunbird species, and has floral traits and a reproduction system that favour allogamy. Our results show that A. mayottensis is a protandrous and partially self-compatible species. Analysis of stigmatic pollen load shows that stigma received a mean of 56 crossed pollen grains and 62.2 selfed pollen grains per stigma. Study of visitation rates of plants and flowers by the sunbird showed that there is daily variation in the activity of this pollinator, and that males are more active than females.Key words: Aloe mayottensis, floral biology, Lomatophyllum, Nectarinia, bird pollinization, sunbirds, Oceanic islands, Mayotte.
Simplified food webs lead to energetic bottlenecks in polluted lakes
Authors: Sherwood Graham D , Kovecses Jennifer , Hontela Alice , Rasmussen Joseph B
Published: July 2002

Very little is known about the consequence of human activities on the flow of energy through natural ecosystems. Here, we present a trophic-based approach to describing energy relationships in pollutant-disturbed lakes, emphasizing the importance of prey diversity in maintaining energy transfer to growing fish. Both diet and community analysis indicated that the food web leading to yellow perch (Perca flavescens) in metal-polluted lakes was extremely simplified compared with reference lakes. Through the application of an in situ marker for fish activity costs (muscle lactate dehydrogenase activity) and through bioenergetic modelling, we show how this has severe consequences on the efficiency of energy transfer to perch from their prey; premature energetic bottlenecks (zero conversion efficiency) occur when successively larger prey types are not available to growing perch. These observations provide a much needed ecological and physiological framework for assessing how energy transfer can be affected in polluted systems. Our approach need not be limited therein but should be applicable to any aquatic system where food web structure is variable and (or) disrupted.
The entrainment envelope of dye-core vortices at submerged hydraulic intakes
Authors: Carriveau E C , Baddour R E , Kopp G A
Published: July 2002

Each winter in Canada, operational difficulties are encountered at various water works resulting from intake blockages caused by frazil ice entrainment. In a lake setting, frazil is a surface phenomenon, the strong downward current produced by a swirling flow, with an intake vortex present, provides a mechanism by which frazil is transported from the water surface to the submerged intake below. Laboratory experiments were conducted to study the entrainment envelope associated with swirling and non-swirling flows into submerged water intakes. Three-dimensional velocity measurements were made with an acoustic Doppler velocimeter. The results clearly show that the entrainment envelope for swirling flow is several times larger than that for non-swirling flow. This paper details, for a given set of conditions, the differences in the non-swirling and swirling flow entrainment envelopes and emphasizes the potential difficulties with frazil ice that vortices can cause at intakes.Key words: vortex, dye-core vortex, submerged hydraulic intake, entrainment envelope, three-dimensional velocity measurements, acoustic Doppler velocimeter.
Soil structure interaction analysis: modeling the interface
Authors: Zeghal Morched , Edil Tuncer B
Published: July 2002

The sandstructure interface, developed under monotonic loading, was modeled based on physical observations. The model takes into account the macroscopic conditions to yield a general constitutive law applicable to a wide range of contact problems and the microstructural considerations constitute the specialization of the general equations to a specific problem. The surface of slippage was idealized to be sinusoidal based on an intensive numerical simulation program that made use of the discrete element technique. The model incorporates the effect of grain crushing found to play a major role in the behavior of the interface. Analysis of laboratory data revealed a close relationship between grain crushing and the work dissipated plastically during shear. The proposed elastoplastic model, requiring a limited number of parameters, predicts the shear stresses for the modified direct shear test and reproduces the shaft resistance of the shaftsand interface pullout tests in a satisfactory manner.Key words: sand-structure interface, microstructure, grain crushing, plastic work.
Ortho substituent effects on transfer of aryl groups from oxygen to carbon in adducts from diaryloxycarbenes and DMAD
Authors: Lu Xiaosong , Warkentin John
Published: July 2002

Diaryloxycarbenes, generated by thermolysis of 2,2-diaryloxy-5,5-dimethyl-Δ3-1,3,4-oxadiazolines in benzene, reacted with dimethyl acetylenedicarboxylate (DMAD) to afford triesters. The triesters arose by aryl-group transfer from oxygen to carbon (ipso substitution). A cyano group in the para position had been shown earlier to favour the ipso substitution whereas a para-methoxy group disfavoured it. Surprisingly, the ortho-methoxy substituent also favoured ipso substitution. As a tentative rationale, we had proposed that a vinylogous diaryloxycarbene intermediate, with dipolar properties, is formed when a diaryloxycarbene attacks at the sp-carbon of DMAD and that an ortho substituent, with one or more unshared electron pairs, can stabilize the intermediate by donating electron density to the positive site. In the present work, support for that interpretation and for the importance of a steric effect, was provided by examining the competition between (i) p-tolyl and phenyl; (ii) o-tolyl and phenyl; (iii) o-iodophenyl and phenyl; (iv) o-iodophenyl and p-chlorophenyl; and (v) o-bromophenyl and p-chlorophenyl as potential migrating groups.Key words: aromatic substitution, carbene, ipso, diaryloxycarbene, oxadiazoline.
An ab initio study of conformations and sigmatropic shifts in triazene and its mono-, di-, and trimethyl derivatives
Authors: Pye Cory C , Vaughan Keith , Glister Julie F
Published: July 2002

A computational study of triazene, methyltriazene, dimethyltriazene, and trimethyltriazene is presented. A number of different conformers are analyzed and rationalized using hyperconjugation and steric interaction arguments. The transition states for rotation, inversion, and proton and methyl shifts (including water-mediated) are found and the barriers determined.Key words: triazene, ab initio, methyltriazene, 1,3-proton shift.
Wood-density variation of Norway spruce in relation to nutrient optimization and fibre dimensions
Authors: Mäkinen Harri , Saranpää Pekka , Linder Sune
Published: July 2002

The effect of fertilization on wood density, fibre length, fibre diameter, lumen diameter, proportion of cell wall area, and cell wall thickness of Norway spruce (Picea abies (L.) Karst.) were studied in a nutrient optimization experiment in northern Sweden. On the fertilized plots, all essential macronutrients and micronutrients were supplied in irrigation water every second day during the growing season. After 12 years' treatment, data were collected from 24 trees (40 years old) on the fertilized and control plots. Fertilization increased radial growth more than threefold, especially earlywood width, and decreased wood density by over 20% at 1.3 and 4 m height. The decrease in wood density was closely related to the proportion of latewood. The absolute wood density also decreased across the whole annual ring but proportionately more in latewood than in earlywood. A close relationship was found between the wood density and fibre properties, especially with the proportion of cell wall in a cross section of each annual ring, as well as with fibre and lumen width. The absolute cell wall thickness was clearly less related to wood density. However, rather large variations were found between individual trees in the relationship between wood density and fibre properties.
Variation in survival rates for the alpine marmot (Marmota marmota): effects of sex, age, year, and climatic factors
Authors: Farand É. , Allainé D , Coulon J
Published: July 2002

We examined variation in annual survival rates in a population of alpine marmots (Marmota marmota) according to intrinsic (sex and age) and extrinsic (year and climate) factors. We tested predictions concerning (i) a sex effect in a monogamous non-dimorphic species, (ii) age structure of survival rates in a mesomammal, and (iii) the annual variability effect and the contribution of stochastic climatic factors, especially snow cover, frost, and rainfall. We used a 8-year dataset of 367 marmots that were livetrapped and marked in La Sassière Nature Reserve in the French Alps between 1990 and 1997. Survival and recapture rates were modelled using recent developments in capturerecapture models. Sex had no effect on survival rates, which agrees with the predictions of sexual selection. Survival rates for young of the year (YOY, from weaning to first birthday) were, on average, lower than in the older age class. In the older age class, annual variation occurred that was strongly related to the intensity of autumn frost. By determining the soil temperature at the beginning of hibernation, this factor, though short-lived, could have determined the energetic cost of hibernation. Neither annual variation nor an environmental effect was detected in YOY despite a large sample size. Social thermoregulation could contribute to the stability of YOY survival rates. As infanticide was common after the immigration of a new dominant male, survival of YOY seemed to depend more on social events than on stochastic climatic ones.
ALL SEPARATING TRIANGLES IN A PLANE GRAPH CAN BE OPTIMALLY "BROKEN" IN POLYNOMIAL TIME
Authors: ACCORNERO ANNA , ANCONA MASSIMO , VARINI SONIA
Published: July 2002

Lai and Leinwand have shown that an arbitrary plane (i.e., embedded planar) graph G can be transformed, by adding crossover vertices, into a new plane graph G′ admitting a rectangular dual. Moreover, they conjectured that finding a minimum set of such crossover vertices is an NP-complete problem. In this paper it is shown that the above problem can be resolved in polynomial time by reducing it to a graph covering problem, and an efficient algorithm for finding minimum set of edges on which to insert the crossover vertices is also presented.
FROM STANDARD TO NON-STANDARD SEMANTICS BY SEMANTICS MODIFIERS
Authors: ABRAMOV SERGEI , GLÜCK ROBERT
Published: July 2002

An approach for systematically modifying the semantics of programming languages by semantics modifiers is described. Semantics modifiers are a class of programs that allow the development of general and reusable "semantics components". Language independence is achieved through the interpretive approach: an interpreter serves as a mediator between the new language and the language for which the non-standard semantics was implemented. Inverse computation, equivalence transformation and neighborhood analysis are shown to be semantics modifiers. Experiments with these modifiers show the computational feasibility of this approach. Seven modifier projections are given which allow the efficient implementation of non-standard interpreters and non-standard compilers by program specialization or other powerful program transformation methods.
PERFORMANCE EVALUATION OF PRACTICAL PARALLEL COMPUTER MODEL LogPQ
Authors: TOUYAMA TAKAYOSHI , HORIGUCHI SUSUMU
Published: July 2002

The present super computer will be replaced by a massively parallel computer consisting of a large number of processing elements which satisfy the continuous increasing depend for computing power. Practical parallel computing model has been expected to develop efficient parallel algorithms on massively parallel computers. Thus, we have presented a practical parallel computation model LogPQ by taking account of communication queues into the LogP model. This paper addresses the performance of a parallel matrix multiplication algorithm using LogPQ and LogP models. The parallel algorithm is implemented on Cray T3E and the parallel performances are compared with on the old machine CM-5. This shows that the communication network of T3E has superior buffering behavior than CM-5, in which we don't need to prepare extra buffering on T3E. Although, a little effect remains for both of the send and receive bufferings. On the other hand, the effect of message size remains, which shows the necessity of the overhead and gap proportional to the message size.
PARALLEL VERTEX COLOURING OF INTERVAL GRAPHS
Authors: SAJITH G. , SAXENA SANJEEV
Published: July 2002

Evidence is given to suggest that minimally vertex colouring an interval graph may not be in NC 1. This is done by showing that 3-colouring a linked list is NC 1-reducible to minimally colouring an interval graph. However, it is shown that an interval graph with a known interval representation and an O(1) chromatic number can be minimally coloured in NC 1.

For the CRCW PRAM model, an o( log n) time, polynomial processors algorithm is obtained for minimally colouring an interval graph with o( log n) chromatic number and a known interval representation. In particular, when the chromatic number is O(( log n)1-ε), 0<ε<1, the algorithm runs in O( log n/ log log n) time. Also, an O( log n) time, O(n) cost, EREW PRAM algorithm is found for interval graphs of arbitrary chromatic numbers. The following lower bound result is also obtained: even when the left and right endpoints of the interval are separately sorted, minimally colouring an interval graph needs Ω( log n/ log log n) time, on a CRCW PRAM, with a polynomial number of processors.
ENTROPY DENSITY FOR RELATIVISTIC QUANTUM FIELD THEORY
Authors: NARNHOFER HEIDE
Published: July 2002

We show how the nuclearity condition of Buchholz and Wichmann allows to define in the ground state a local entropy with the desired properties despite the fact that local algebras are type III. Generalization to temperature states is also possible so that thermodynamic functions also exist in the context of relativistic quantum field theory.
Square-Integrability of Induced Representations of Semidirect Products
Authors: Aniello P. , Cassinelli Gianni , de Vito Ernesto , Levrero Alberto
Published: July 2002

We consider a semidirect product G=A×′H, with A abelian, and its unitary representations of the form [Formula: see text] where x0 is in the dual group of A, G0 is the stability group of x0 and m is an irreducible unitary representation of G0∩H. We give a new selfcontained proof of the following result: the induced representation [Formula: see text] is square-integrable if and only if the orbit G[x0] has nonzero Haar measure and m is square-integrable. Moreover we give an explicit form for the formal degree of [Formula: see text].
FOUR EASY PIECES — EXPLICIT R MATRICES FROM THE $(\dot 0_m |\alpha)$ HIGHEST WEIGHT REPRESENTATIONS OF Uq[gl(m|1)]
Authors: DE WIT DAVID
Published: July 2002

We provide explicit presentations of members of a suite of R matrices arising from the [Formula: see text] representations of the quantum superalgebras Uq[gl(m|1)]. Our algorithm constructs both trigonometric and quantum R matrices; all of which are graded, in that they solve a graded Yang–Baxter equation. This grading is easily removed, yielding R matrices that solve the usual Yang–Baxter equation. For m > 2, the computations are impracticable for a human to perform, so we have implemented the entire process in MATHEMATICA, and then performed the computations for m = 1, 2, 3 and 4.
PATTERN CHARACTERIZATION: A CASE STUDY IN OSMOSEDIMENTATION
Authors: NETO C. RODRIGUES , ROSA R. R. , RAMOS F. M.
Published: July 2002

In the present work, we investigate the ability of recently proposed computational operators to characterize the problem of pattern formation by fluid flow and mass transport in a viscous binary fluid mixture under osmosedimentation. We perform a numerical investigation of these patterns using three computational operators (R2 → R), computed from the spatial mass distribution, the streamlines, and the velocity fields. Our main goal is to demonstrate the ability of these computational operators to distinguish different dynamical regimes in the complex patterns arising from the osmosedimentation process.
PARALLEL PATTERN MATCHING WITH SCALING
Authors: MONGELLI H. , SONG S. W.
Published: July 2002

Given a text and a pattern, the problem of pattern matching consists of determining all the positions of the text where the pattern occurs. When the text and the pattern are matrices, the matching is termed bidimensional. There are variations of this problem where we allow the matching using a somehow modified pattern. A modification that we will allow is that the pattern can be scaled. We propose a new parallel algorithm for this problem, under the CGM (Coarse Grained Multicomputer) model. This algorithm requires linear local computing time in the input, linear memory and uses only one communication round, during which at most a linear amount of data is exchanged. To be the best of our knowledge, there are no known parallel algorithms for the bidimensional pattern matching problem with scaling in the literature. This proposed algorithm was implemented in C, using the PVM interface and was executed on a Parsytec PowerXplorer parallel machine. The experimental results obtained were very promising and showed significant speedups.
PERTURBATIVE BETA-FUNCTION OF N=2 SUPER YANG-MILLS THEORIES
Authors: MAGGIORE NICOLA
Published: July 2002

The BRST algebraic proofs of the nonrenormalization theorems for the β-functions of N=2 and N=4 Super Yang-Mills theories are reviewed.
A FIELD-THEORETIC APPROACH TO CONNES' GAUGE THEORY ON M4 × Z2
Authors: KASE HIROMI , MORITA KATSUSADA , OKUMURA YOSHITAKA
Published: July 2002

Connes' gauge theory on M4 × Z2 is reformulated in the Lagrangian level. It is pointed out that the field strength in Connes' gauge theory is not unique. We explicitly construct a field strength different from Connes' and prove that our definition leads to the generation-number independent Higgs potential. It is also shown that the nonuniqueness is related to the assumption that two different extensions of the differential geometry are possible when the extra one-form basis χ is introduced to define the differential geometry on M4 × Z2. Our reformulation is applied to the standard model based on Connes' color-flavor algebra. A connection between the unimodularity condition and the electric charge quantization is then discussed in the presence or absence of νR.
A COMMENT ON THE BLACK HOLE INFORMATION PARADOX
Authors: MATHUR SAMIR D.
Published: July 2002

Results from string theory strongly suggest that formation and evaporation of black holes is a unitary process. Thus we must find a flaw in the semiclassical reasoning that implies a loss of information. We propose a new criterion that limits the domain of classical gravity: the hypersurfaces of a foliation cannot be stretched too much.
AN INVESTIGATION INTO THE FERMILAB APPROACH TO HEAVY QUARKS ON THE LATTICE
Authors: SROCZYNSKI ZBIGNIEW
Published: July 2002

We use a space-time asymmetric O(a) improved fermion action and fix the asymmetry non-perturbatively to restore the relativistic dispersion relation. We compute spectra and matrix elements of quarkonia and heavy-light mesons and compare with results obtained using a symmetric action with the Fermilab interpretation i.e. that the physics of heavy lattice quarks depends solely on their kinetic mass. We provide additional evidence to support this.
HIGGS MASS IN THE STANDARD MODEL FROM COUPLING CONSTANT REDUCTION
Authors: ANANTHANARAYAN B. , PASUPATHY J.
Published: July 2002

Plausible interrelations between parameters of the standard model are studied. The empirical value of the top quark mass, when used in the renormalization group equations, suggests that the ratio of the color SU(3) gauge coupling g3, and the top coupling gt is independent of the renormalization scale. On the other hand, the variety of top-condensate models suggests that the Higgs self-coupling λ is proportional to [Formula: see text]. Invoking the requirement that the ratio [Formula: see text] is independent of the renormalization scale t, fixes the Higgs mass. The pole mass of the Higgs (which differs from the renormalization group mass by a few percent) is found to be ~ 154 GeV for the one-loop equations and ~ 148 GeV for the two-loop equations.
EFFECT OF A MAGNETIC FIELD ON THE BROKEN ELECTROWEAK SYMMETRY
Authors: QUERTS E. RODRÍGUEZ , CRUZ A. MARTÍN , ROJAS H. PÉREZ
Published: July 2002

We discuss the effect of a strong magnetic field in the behavior of the symmetry of an electrically neutral electroweak plasma. We analyze the case of a strong field and low temperatures as compared with the W rest energy. If the magnetic field is large enough, it is self-consistently maintained. It is shown that the charged vector bosons play the most important role, leading only to a decrease of the symmetry breaking parameter, the symmetry restoration not being possible.
CROSSOVER BETWEEN THE ELECTRON–HOLE PHASE AND THE BCS EXCITONIC PHASE IN QUANTUM DOTS
Authors: RODRIGUEZ BORIS A. , GONZALEZ AUGUSTO , QUIROGA LUIS , RODRIGUEZ FERNEY J. , CAPOTE ROBERTO
Published: July 2002

Second order perturbation theory and a Lipkin–Nogami scheme combined with an exact Monte Carlo projection after variation are applied to compute the ground-state energy of 6≤N≤210 electron–hole pairs confined in a parabolic two-dimensional quantum dot. The energy shows nice scaling properties as N or the confinement strength is varied. A crossover from the high-density electron–hole phase to the BCS excitonic phase is found at a density which is roughly four times the close-packing density of excitons.
FINITE TEMPERATURE FIELD THEORY OF BOSE-EINSTEIN CONDENSATES
Authors: HUTCHINSON D. A. W.
Published: July 2002

The field theory treatments of Base condensed systems developed forty years ago have received renewed attention within the context of inhomogeneous systems since the realisation of Base-Einstein condensation in dilute trapped alkali gases in 1995. These experiments allow quantitative tests of the theories used to describe them and hence provide a unique laboratory in which to evaluate and develop these field theoretical methods to an unprecedented degree. Various examples are discussed to illuminate these developments.
ANTI-RESONANCES OF TUNNELING THROUGH A QUANTUM WIRE WITH SIDE-COUPLED QUANTUM DOTS
Authors: FENG JIN-FU , XIONG SHI-JIE
Published: July 2002

We study the transport properties of electrons in a quantum wire with side-coupled quantum dots in Coulomb blockade regime by the use of the equivalent single-particle multi-channel network and Landauer formula. At low temperatures the calculated dependence of the conductance on the gate voltage of dots exhibits two dips, indicating the destructive interference of the wave directly transmitted through the wire and the wave reflected from the dots. In a wire with more than one side-coupled dots the suppression of conductance is a simple summation of the effects of scattering of all the dots. The possibility of fabricating tunable switch devices by using such structures is discussed.
NaV2O5: AN EXOTIC EXCITON SYSTEM
Authors: MOSTOVOY MAXIM V. , KHOMSKII DANIEL I. , KNOESTER JASPER
Published: July 2002

We show that the phase transition which sodium vanadate undergoes at Tc=34 K is driven by a charge ordering. The relevant effective Hamiltonian is of the Frenkel exciton type, with a very large bandwidth to molecular energy ratio. This causes stron non-Heitler-London effects and a temperature dependent gap that vanishes at Tc. In addition to the phase transition, the model qualitatively explains the observed absorption spectrum and the anomaly in the static dielectric constant. Within our model, the observed spin-gap opening at Tc results from exciton-spinon coupling.
BANDGAP RENORMALIZATION DUE TO HIGH-DENSITY CARRIERS IN ZnO EPITAXIAL THIN FILMS
Authors: YAMAMOTO AISHI , KIDO TAKEO , GOTO TAKENARI , CHEN YEFAN , YAO TAKAFUMI
Published: July 2002

Renormalized bandgap energy due to high-density carriers in ZnO is calculated and compared with our experimental results. Two different reported treatments for the correlation energy are employed for the calculation, and we prove that Beni and Rice's model sufficiently explains the experimental data. Furthermore, we calculate optical gain spectrum, which reproduces well the experimental data.
ANDERSON TRANSITION IN TWO-DIMENSIONAL DISORDERED LATTICES WITH LONG-RANGE COUPLING
Authors: RODRÍGUEZ A. , MALYSHEV V. A. , DOMÍNGUEZ-ADAME F. , LEMAISTRE J. P.
Published: July 2002

We provide arguments indicating that an Anderson transition may exist in two-dimensional disordered systems with long-range coupling. As a working example, a two-dimensional dipolar Frenkel exciton Hamiltonian is used in order to confirm the existence of a localization-delocalization transition. It is found that the states of one of the band tails, but not of the band center, undergo the continuous Anderson transition.
BRIDGING-HALOGEN DEPENDENCE OF ULTRAFAST DYNAMICS OF EXCITONS IN QUASI-ONE-DIMENSIONAL PLATINUM COMPLEXES
Authors: TOMIMOTO SHINICHI , SAITO SHINGO , SUEMOTO TOHRU , SAKATA KOJI , TAKEDA JUN , KURITA SUSUMU
Published: July 2002

The femtosecond time-resolved luminescence of a quasi-one-dimensional halogen-bridged platinum complex [ Pt(en) 2][ Pt(en) 2 I 2] (CIO4)4 (abbreviated as Pt-I) is observed. The observed lifetime of the exciton luminescence is rather shorter than those of the other Pt-X (X = halogen ion) systems which have relatively wider band gaps. This result is considered to show that the nonradiative relaxation process becomes more efficient in the narrow-gap system Pt-I.
PREPARATION AND CHARACTERISATION OF Ti/BaTiO3/InP MIS STRUCTURES
Authors: SONIA G. , KUMAR M. SENTHIL , ARIVUOLI D. , KUMAR J. , BASKAR K.
Published: July 2002

Indium Phosphide (InP) is one of the most promising materials for high-speed electronic and optoelectronic devices. In the present investigation n-type InP substrates of <111> orientation grown by LEC technique in our laboratory were used to study the surface state densities. The wafer was polished with HBr:K 2 Cr 2 O 7: H 2 O (BCA) polishing solution and decreased with organic solvents. Au:Ge was used has a back ohmic contact and the wafer was annealed at 623K for 5 min. under nitrogen ambient. Barium Titanante ( BaTiO 3), a dielectric material was used as an insulator to fabricate InP -MIS structures. BaTiO 3 thin film has been deposited on InP substrates by sol-gel technique through organic precursor route. Titanium metal contact was made on the BaTiO 3 to obtain MIS structure. Compositional analysis of the BaTiO 3 thin film on InP substrates has been carried out using XPS and EDX. By the Capacitance Voltage measurements a minimum surface state density ( N ss) value as low as 4.5 × 1010 cm -2 eV -1 has been obtained for Ti/BaTiO 3/ InP MIS structures which is comparatively less than that of other deposited insulators.
APPLICATION OF CVD DIAMOND FILMS FOR UV THERMOLUMINESCENCE DOSIMETER
Authors: AHN J. , GAN B. , ZHANG Q. , YOON S. F. , LIGATCHEV V. , WANG S.-G. , HUANG Q.-F. , CHEW K. , MELÉNDREZ R. , BARBOZA-FLORES M.
Published: July 2002

This study presents the investigation of CVD diamond for the application of an UV TL dosimeter. A 9-μm-thick film used in this study presents a TL glow curve with a well-defined first-order kinetic peak (at about 273 K), which norm ally presents in the glow curve from ionizing radiations, is not observed. By fitting the glow curve to a first-order kinetic model, the trap activation energy E t = 0.95 eV and frequency factor s = 5.6 x 106 s -1 have been resolved.
THEORETICAL ASPECTS OF THE FIELD INDUCED SUPERCONDUCTIVITY IN POLYACENES AND C60
Authors: DRECHSLER S.-L. , PAASCH G. , MÁLEK J. , SHULGA S. V. , ESCHRIG H. , ROSNER H.
Published: July 2002

The electronic structure and the superconductivity in field-doped polyacenes are considered. Within a modified Thomas–Fermi approach for typical experimental values of the surface charge density the injected charge is confined to a monolayer. The electron–phonon coupling constant for internal modes λintra is estimated using the work of Devos and Lanoo (Ref. 4) and the density of states N(0) estimated from a 2D tight-binding model derived from a full potential LDA band structure calculation for bulk anthracene. The empirical values of the Coulomb pseudopotentials are significantly enhanced. The strong Coulomb interaction is considered as a key quantity which determines the large differences in the critical temperatures achieved for n-doped polyacenes and C 60.
QUANTUM DYNAMICS AND RANDOM MATRIX THEORY
Authors: KUNZ HERVÉ
Published: July 2002

We compute the survival probability of an initial state, with an energy in a certain window, by means of random matrix theory. We determine its probability distribution and show that is is universal, i.e. characterised only by the symmetry class of the hamiltonian and independent of the initial state.
The Effects of Surface Contamination on the Biaxially Textured Substrate for YBCO Thick Film Deposition
Authors: Apicella M. L. , Boffa V. , Celentano G. , Fabbri F. , Petrisor T.
Published: July 2002

The epitaxial growth of YBa 2 Cu 3 O 7-x (YBCO) films on biaxially textured substrates is one of the most promising technique for the fabrication of high current superconducting tapes operating at high temperature. Ni is very attractive as substrate because it easily develops a (100)[001] cubic texture. The low oxidation resistance represents the main drawback of the Ni substrate. In order to better assess the role of oxygen on the Ni substrates, a surface physics technique as Auger spectroscopy has been used. It has allowed to evaluate the amount of impurities for different Ni processing and exposure to the air. The results demonstrate that the surface contamination can be efficiently removed by RF sputtering before buffer layer deposition. This procedure allows to obtain CeO 2/Pd/Ni architecture by laser ablation with a good epitaxy both of Pd and CeO 2 films. On the contrary, when CeO 2 is directly deposited on Ni a low epitaxy is obtained. The Auger analysis confirms that the formation of (111) NiO at the Ni - CeO 2 interface hampers the epitaxial growth of the ceria film.
Magnetic Properties of Biaxially Oriented NI-V Substrate
Authors: Bettinelli D. , Petrisor T. , Gambardella U. , Boffa V. , Ceresara S. , Nistor L. , Pop V. , Scardi P.
Published: July 2002

The paper presents the structural and magnetic properties of a new non-magnetic biaxially textured substrate based on Ni 100-x V x solid-solution for YBa 2 Cu 3 O 7-y tape fabrication. The effective atomic magnetic moment monotonously decreases with the vanadium concentration, causing a corresponding decrease of Curie temperature. The Curie temperature reaches the zero value at about 11.5. % of vanadium. The texturing studies revealed that (100)[001] cube texture can be easily developed up to x=11 at. %, by a cold rolling process followed by a recrystallization thermal treatment. The X-ray ω and ϕ scans have demonstrated that the samples have a good out-of-plane and in-plane texture for the whole solubility range, with FWHM of 7° and 11°, respectively. The correlation between the magnetic and structural anisotropy was also studied.
POSSIBLE P-WAVE CONDENSED CONDUCTOR (OR SUPERCONDUCTOR) FOR La1-xCaxMnO3 FILMS
Authors: Kim Hyun-Tak , Kim Yong-Jihn , Kang Kwang-Yong
Published: July 2002

A ferromagnetic phase with electron carriers and a semiconducting phase with hole carriers were separated in La 1-x Ca x MnO 3 thin films by the van der Pauw method. We conclude that two phases are attributed to the metal-insulator instability. In the ferromagnetic phase for films with anisotropic moments in two dimensions, a remnant resistivity of the order of 10-8Ωm is observed up to 100 K and increases exponentially with temperature up to Tc and above one Tesla as a function of magnetic field strength (a positive magnetoresistivity). The phase below Tc is regarded as a polaronic state with a polaronic tunneling conduction. Possible p-wave condensation (or superconductor) with a parabolic density of states and the phase separation are discussed on the basis of the two-fold degeneracy of eg orbitals.
CHEMICAL COMPOSITION AND CRYSTALLINE PHASES IN F-DOPED TIN OXIDE FILMS GROWN BY DC REACTIVE SPUTTERING
Authors: MARTEL A. , CABALLERO-BRIONES F. , IRIBARREN A. , CASTRO-RODRÍGUEZ R. , BARTOLO-PÉREZ P. , PEÑA J. L.
Published: July 2002

We study by x-ray diffraction (XRD) the structural variations on a series of SnOx:F films grown by dc reactive sputtering from a metallic tin target in an Ar- O 2-Freon plasma. We found that the films tend to be crystalline when the stoichiometry approaches to that of SnO or SnO 2, being amorphous in between. We fitted the x-ray diffractograms and found that films are composed by a mixture of compounds, i.e. SnO, Sn 3 O 4, Sn 2 O 3 and SnO 2, given by the simultaneous presence of Sn +2 and Sn +4. From the analysis of the deconvoluted areas under the x-ray diffractograms we calculate the Sn +2/ Sn and Sn +4/ Sn molar fraction present in the films. The same calculations are done for the x-ray photoelectron spectroscopy (XPS) results. By applying a combinatory model we fitted the general behavior of SnO x films with different oxygen content versus the Sn +2/ Sn and Sn +4/ Sn molar fraction. Both XRD and XPS results are compared with the theoretical curve, showing a well agreement.
LOCAL ARRANGEMENT EFFECTS ON THE STATISTICAL PROPERTIES OF THE EFFECTIVE CONDUCTIVITY AND FIELD IN 2D COMPOSITES
Authors: ZEKRI L. , ZEKRI N.
Published: July 2002

We study the effect of the local arrangement of the metallic grains in metal-dielectric composite films on the statistical properties of the effective conductivity and the local field at the percolation threshold and for a characteristic frequency (where the conductivities of the two components are of the same magnitude). It is found that the segregation enhances sensitively the effective conductivity of the system as well as the local field. Further discussions on the field localization and other phenomena are provided.
SYNTHESIS AND CHARACTERIZATION OF La2Ca3Cu4Oy
Authors: JEYABALAN K. , KALIYAPERUMAL L. K.
Published: July 2002

Synthesis and characterization of La 2 Ca 3 Cu 4 O y compound is reported here. The powder X-ray diffraction analysis shows that the system belongs to an orthorhombic structure and the lattice parameters are a = 3.814(4)Å, b = 3.930(5)Å and c = 34.772(3)Å.
MICROSCOPIC DETERMINISTIC DYNAMICS AND PERSISTENCE EXPONENT
Authors: ZHENG B.
Published: July 2002

Numerically, we solve the microscopic deterministic equations of motion with random initial states for the two-dimensional ϕ4 theory. Scaling behavior of the persistence probability at criticality is systematically investigated and the persistence exponent is estimated.
CROSS-LANGUAGE TEXT RETRIEVAL BY QUERY TRANSLATION USING TERM REWEIGHTING
Authors: KANG INSU , KWON OH-WOOG , LEE JONG-HYEOK , LEE GEUNBAE
Published: July 2002

In a dictionary-based query translation for cross-language text retrieval, transfer ambiguity is one of the main causes of performance deterioration, but the problem has not received significant attention in this field. To resolve transfer ambiguity, this paper proposes a two-phase query translation based on term reweighting, which uses a bilingual transfer dictionary, originally designed for machine translation. In general, source language query terms each show some word association with others, so that their correct translations should be more likely to co-occur in target documents. Based on this simple intuition, the first phase discriminates more relevant target documents from the others. Using statistical and ranking information from the highly relevant documents, the second phase then converts a translated query vector into reweighted form to add an extra weight on probably correct target terms. In experiments, the results were remarkable: the proposed method achieved almost the same performance as the monolingual IR system, actually contributing to an improvement of precision by about 9% over a baseline system.
THE DISTRIBUTION OF PERIODIC AND APERIODIC PATTERN EVOLUTIONS IN RINGS OF DIFFUSIVELY COUPLED MAPS
Authors: LIND PEDRO G. , CORTE-REAL JOÃO A. M. , GALLAS JASON A. C.
Published: July 2002

This paper reports histograms showing the detailed distribution of periodic and aperiodic motions in parameter-space of one-dimensional lattices of diffusively coupled quadratic maps subjected to periodic boundary conditions. Particular emphasis is given to the parameter domains where lattices support traveling patterns.