bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal and Molecular Structure of N-(3,5-Dichloro-2-hydroxybenzylidene)- and N-(2-Hydroxy-3-methoxybenzylidene)aniline Oxides. Delocalisation in the Spacer of the Intramolecular H-Bond and the Problem of Quasi-Aromaticity
Authors: Krygowski Tadeusz M. , Stępień Beata , Anulewicz-Ostrowska Romana , Cyrański Michał K. , Grabowski Sławomir J. , Rozwadowski Zbigniew , Dziembowska Teresa
Published: July 2002

The hydrogen bond in the title compounds and their analogues with the spacer built of six heavy atoms (O,N,C,C,C,O) between the H-donor OH group and H-acceptor oxygen atom in the oxide group is much stronger than in the case of spacers with five heavy atoms. In spite of that, the delocalisation in the spacer does not depend on the strength of the H-bond, leading to the conclusion that quasi-aromaticity is not a proper term for these kinds of pseudorings. This is supported by analysis of the geometry of N-(3,5-dichloro-2-hydroxybenzylidene)- and N-(2-hydroxy-3-methoxybenzylidene)aniline oxides presented in this study and molecular geometries of five well solved structures retrieved from the CSD. Schleyer's index of aromaticity, NICS, is positive (i.e. indicating nonaromatic behaviour) for a model approximating the title H-bond system spacer indicating no ring current in the pseudoring whereas Li+-chelated system exhibits a slightly aromatic property (NICS < 0).
Comparison of Procedures for Isolation of Monoterpene Hydrocarbons from Fresh Needles of Picea abies and Picea omorica
Authors: Holubová Valerie , Chvílíčková Iva , Kubáň Vlastimil
Published: July 2002

Extraction procedures (steam distillation, supercritical fluid extraction and solvent extraction) for isolation of monoterpene hydrocarbons from fresh needles of Picea abies and Picea omorica were optimised. The procedures were compared with the aim of minimizing consumption of needles and improving the extraction efficiency and repeatability. An influence of homogenisation procedures and storage conditions (liquid nitrogen, -18 and 4 °C) on the total content and composition of essential oils was studied. Cryogenic grinding (liquid nitrogen) combined with the extraction with cold hexane (extraction time 2 h) and subsequent GC-MS determination in freshly homogenised needles gives the best results (1.5-4 times better extraction efficiency, RSD < 10% for P. abies and < 25% for P. omorica). Limits of detections (3 S/N) for individual monoterpene hydrocarbons from units to tens of ng/g and recoveries 97.2-101.4% were found in fresh needles (calculated to fresh weight). While cooling to 4 °C is unacceptable, freezing at -18 °C for the period of 18 days in the dark gives also good results.
Catalytic Properties of a Heated Ammonium-Saturated Dioctahedral Smectite
Authors: Jankovič Ľuboš , Komadel Peter
Published: July 2002

A series of acid catalysts was prepared by heating of NH4-saturated montmorillonite at 200-600 °C for 24 h. Their catalytic activity was tested in acetylation of 3,4,5-trimethoxybenzaldehyde with acetic anhydride. This reaction is sufficiently sensitive to modification of the catalyst and thus suitable for testing catalytic activity of modified montmorillonites. Most of the prepared catalysts were able to catalyse the test reaction and produce diacetate in higher than 50% yields. The most active catalyst was obtained after heating at 300 °C. It was slightly less effective than commercially available acid-activated K10 catalyst.
Crystal Structures of Two New Cyclosporin Clathrates
Authors: Hušák Michal , Kratochvíl Bohumil , Císařová Ivana , Jegorov Alexandr
Published: July 2002

Two isomorphous clathrates formed by dihydrocyclosporin A or cyclosporin V with tert-butyl methyl ether are reported and compared with the structures of related P21-symmetry cyclosporin clathrates. The cyclosporin molecules in both structures are associated via van der Waals interactions forming cavities occupied by solvent molecules (cyclosporin : tert-butyl methyl ether is 1 : 2).
Syntheses of New Triethylene Glycol Bis(alkyl Phosphate)s as Potential Complexing Agents
Authors: Novoměstská Věra , Herrmann Eckhard , Lubal Přemysl , Příhoda Jiří
Published: July 2002

A series of triethylene glycol bis(alkyl phosphate)s HO(RO)P(O)(OCH2CH2)3OP(O)(OR)OH 4 (R = octyl (4a), 1-methylheptyl (4b), 2-ethylhexyl (4c), nonyl (4d), decyl (4e), dodecyl (4f), hexadecyl (4g), octadecyl (4h)) has been synthesized with the expectation that these compounds could be effective complexing and/or extraction agents for metal cations. The compounds were characterized by 31P NMR, 1H NMR, 13C NMR and IR spectroscopy, MALDI-TOF mass spectroscopy and elemental analysis.
New Calix[4]arene-Based Amides - Their Synthesis, Conformation, Complexation
Authors: Stibor Ivan , Růžičková Martina , Krátký Rostislav , Vindyš Michal , Havlíček Jaroslav , Pinkhassik Evguenni , Lhoták Pavel , Mustafina Asiya R. , Morozova Yuliya E. , Kazakova Ella Kh. , Gubskaya Valentina P.
Published: July 2002

New chiral calix[4]arene-based diol-diamides 1a, 1b, tetraamides 2a, 2b and 7 as well as achiral diamide 3 and tetraamides 4-6 were prepared. The conformation of 1 has been studied in solution by NMR and in solid state by X-ray crystallography. The pinched-cone conformation of the calix[4]arene skeleton in 1 was found to be stabilized by a circular array of hydrogen bonds formed by two phenolic O-H and two amidic N-H bonds at lower rim. Whereas no significant complexation of Na+ was observed in solution for diamides 1 and 3, tetraamides 2, 4, 5, and 6 give strong complexes with Na+ as confirmed by NMR titrations of 2 and 4. The influence of anions and the solvents used on complexation ability of 2 towards Na+ is negligible.
Syntheses of Dexamethasone Conjugates of the Phytohormones Gibberellin A3 and 24-Epicastasterone
Authors: Kolbe Adelheid , Kramell Robert , Porzel Andrea , Schmidt Jürgen , Schneider Gernot , Adam Günter
Published: July 2002

The syntheses of N-[10-(9α-fluoro-11β,17α-dihydroxy-16α-methyl-3-oxoandrosta-1,4-diene-17β-carboxamido)decyl]gibberellamide (7) and 6-[({N-[10-(9α-fluoro-11β,17α-dihydroxy- 16α-methyl-3-oxoandrosta-1,4-diene-17β-carboxamido)decyl]carbamoyl}methoxy)imino]-24-epicastasterone (10) are described. [(Benzotriazol-1-yl)oxy]bis(pyrrolidin-1-yl)methylium hexafluorophosphate (HBPyU) was used as the coupling agent for the reaction of gibberellic acid as well as of 24-epicastasterone-O-(carboxymethyl)oxime with N-(10-aminodecyl)- 9α-fluoro-11β,17α-dihydroxy-16α-methyl-3-oxoandrosta-1,4-diene-17β-carboxamide (4). The gibberellic acid conjugate 7 was also synthesised by the coupling of succinimidyl gibberellate 6 with amine 4.
Chorea disclosing deterioration of polycythaemia vera
Authors: Nazabal Eduardo Rubio , Lopez José Marey , Perez Purificación Alvarez , Del Corral Pablo Rey
Published: July 2002

Neurological manifestations occur frequently in polycythaemia. Chorea, however, is a rare complication of the disease. A case of chorea in a patient previously diagnosed with polycythaemia vera is reported. Choreic movements started after measurement of haematological variables showed deterioration. It was considered that this was caused by inappropriate treatment with iron because the chorea was markedly reduced after the two first venesections and normalisation of the packed cell volume and haemoglobin parameters.
Nephrotic syndrome and mesenteric infarction secondary to metastatic mesothelioma
Authors: Farmer C K T , Goldsmith D J A
Published: July 2002

Malignant mesothelioma can present insidiously with progressive breathlessness and chest pain. Paraneoplastic, or non-chest related, presentations are very rare. The case of an elderly man with occupational exposure to asbestos who presented with nephrotic syndrome due to minimal change nephropathy in the context of advanced pleural mesothelial malignancy is reported.
Lung carcinoid related Cushing's syndrome: report of three cases and review of the literature
Authors: Amer K M A , Ibrahim N B N , Forrester-Wood C P , Saad R A , Scanlon M
Published: July 2002

Three patients with lung carcinoid related Cushing's syndrome (LCRCS) treated at Frenchay Hospital, Bristol between 1984 and 1994 are described. The first patient presented with hyperpigmentation 13 years after bilateral adrenalectomy. The second patient had no recurrence or metastases 14 years after removal of a typical carcinoid tumour. The last patient survived nine years after diagnosis of liver metastasis. The possibility of LCRCS should be considered in every patient proved to have Cushing's disease and bilateral adrenal enlargement on abdominal computed tomography. Biochemical sets of investigation (for example, adrenocorticotrophic hormone (ACTH) stimulation, dexamethasone suppression, and metyrapone response) could be misleading and should not be relied upon solely. Search for an ectopic ACTH source should be called off only when ACTH has been demonstrated in the surgically removed specimen, and most importantly, when the serum ACTH concentration returns to normal after surgery. Lung carcinoid tumours are compatible with long survival, and liver metastasis could prove indolent and slowly growing.
Pseudoarthrosis in neurofibromatosis type-1
Authors: Kaur S , Thami G P , Kanwar A J
Published: July 2002

A 27 year old man presented with multiple papules, nodules, and hyperpigmented spots on the body, which he had had since early childhood. In addition, he had a deformity of the right forearm. Examination revealed multiple large sized café-au-lait macules, axillary freckling, and soft cutaneous neurofibromas (mollusca fibrosa). The right forearm was grossly shortened with a length of only 12 cm (fig 1). It presented a globular appearance and on palpation the forearm bones had a break in their continuity. There was hypermobility at the wrist and elbow joints in addition to abnormal movements through the forearm. The left forearm was 28 cm in length and bones were normal. Radiological examination revealed pseudoarthrosis in the mid-part of right forearm involving both the radius and ulna, dislocation of humeroulnar joint, radioulnar diastasis, and a decrease in the bone density (fig 2). On ophthalmological examination, there were multiple bilateral Lisch nodules. A diagnosis of neurofibromatosis type-1 and pseudoarthrosis as a complication was thus established.
Expression of borage Δ6 desaturase in Saccharomyces cerevisiae and oilseed crops
Authors: Qiu Xiao , Hong Haiping , Datla Nagamani , MacKenzie Samuel L , Taylor David C , Thomas Terry L
Published: July 2002

The borage Δ6 desaturase is a modular protein that contains a cytochrome b5-like domain attached to the N-terminus of the main catalytic domain. When the full-length open reading frame was expressed in two types of Saccharomyces cerevisiae strains, the endogenous cytochrome b5-disrupted strain and the cytochrome b5-competent wild type strain, the expressed enzyme introduced a double bond at the Δ6 position into the endogenous substrates 16:1(9) and 18:1(9), and also into the exogenously fed fatty acid substrates 18:2(9,12) and 18:3(9,12,15). However, the preferred substrates of the enzyme when expressed in yeast were 18:2(9,12) and 18:3(9,12,15), whereas 16:1(9) and 18:1(9) were relatively poor substrates. When the partial desaturase sequence with a deletion of the cytochrome b5-like domain at the N-terminus was introduced into the yeast strains, the truncated enzyme could not desaturate any of the supplied substrates. Introduction of the full-length cDNA into flax (Linum usitatissimum L.) under the control of a constitutive (35S) promoter resulted in accumulation of the two Δ6 desaturated fatty acids (18:3(6,9,12) and 18:4(6,9,12,15)), in one elite line, forming up to 22% of the total fatty acids in the stem, 19% in the root, and 11% in the leaf. Introduction of the desaturase into Brassica juncea (L.) Czern. under the control of the Brassica napus L. napin promoter resulted in accumulation of the Δ6 desaturated fatty acids at levels of up to 13% of the total fatty acids in mature seeds.Key words: borage, Δ6 desaturase, γ-linolenic acid, stearidonic acid, Brassica juncea, flax.
Effect of lactoferrin onHelicobacter felisinduced gastritis
Authors: Dial Elizabeth J , Lichtenberger Lenard M
Published: July 2002

Lactoferrin possesses antibiotic, antiinflammatory, and immune-modulating properties that may be active against the gastritis-, ulcer- and cancer-inducing bacterium Helicobacter pylori. In vitro testing of bovine and human lactoferrin by several laboratories has shown significant bacteriostatic and bactericidal activity. Subsequent in vivo testing of bovine lactoferrin in animal models of H. pylori infection has shown beneficial effects of this agent. Our laboratory has utilized a mouse model that is infected with the feline strain of this bacterium, H. felis. The resulting gastritis that develops in this model and the effects of bovine lactoferrin and recombinant human lactoferrin (from Aspergillus niger var. awamori, Agennix Inc., Houston, Tex.) treatment were assessed by various measures. Infected animals treated with orally administered lactoferrin showed reversals in all parameters. In addition, when recombinant human lactoferrin was used in combination with low doses of amoxicillin or tetracycline, there was an enhancement in gastritis-reducing activity. Possible mechanisms for these effects of lactoferrin are discussed. Lactoferrin has significant, orally active in vivo actions and should be further investigated for clinical situations involving Helicobacter infections where it may have utility when administered alone and also when given in combination with established antibiotic agents.Key words: lactoferrin, Helicobacter, gastritis, surface hydrophobicity.
Purification, physicochemical properties, and subcellular location of alkaline inorganic pyrophosphatase from sesame (Sesamum indicumL.) cotyledons
Authors: Hemalatha K PJ , Prasad D Siva
Published: July 2002

Changes in the levels of inorganic pyrophosphatases (PPases) were monitored in germinating sesame seeds at regular intervals. Activities of acid and alkaline PPases increased markedly in cotyledons up to day 4, remained at the peak level up to day 7, and then showed a considerable decline thereafter. An alkaline PPase was isolated and purified from 5-day-old sesame cotyledons following acetone precipitation, ammonium sulfate fractionation, and chromatography on DEAE-Sephadex. Current protocol yielded about 20% recovery of total activity with a 6.4-fold purification. The enzyme was a monomer with a molecular mass of 20.8 kDa. Some of the properties of alkaline PPase including stability, substrate specificity, ion requirement, and amino acid composition were studied. Alkaline PPase showed maximum activity at pH 8.6 in the presence of Mg2+and at 50°C. However, the metal ion could not protect the enzyme against thermal denaturation. Alkaline PPase was highly specific for inorganic pyrophoaphate (PPi) as substrate and the Kmvalue was 0.7677 ± 0.0528 mM. Full activation of the enzyme was achieved with a Mg2+/PPiratio of 2. Divalent metal ions such as Ca2+, Cu2+, and Zn2+inhibited PPase activity. Mg2+partially relieved the inhibition caused by adenosine 5'-triphosphate. Studies related to the localization of alkaline PPase in microbodies revealed that the enzyme was distributed between glyoxysomes and mitochondria, with the former containing more of it.Key words: Sesamum indicum, cotyledons, alkaline inorganic pyrophosphatase, purification, properties.
Field study of geochemistry and solute fluxes in flooded uranium mine tailings
Authors: Peacey Vicky , Yanful Ernest K , Payne Roger
Published: July 2002

A geochemical investigation was conducted at the Quirke cell 14 mine waste management area near Elliot Lake, Ontario, Canada, to assess the evolution of water quality of submerged preoxidized uranium mine tailings. Dissolved solids, sulphate, and radium fluxes towards the water cover were calculated using measured solute concentrations, water-cover volumes, and seepage rates for 1993 and 1999. Results indicate that flooding of preoxidized tailings can lead to the initial release of dissolved solids, acidity, and sulphate from the tailings to the overlying water cover. However, the overall impact of this release on the water cover can be minimal in the long term because of dilution from precipitation and fresh water inflows and flushing of the oxidation products down into the pore water. Profiles of dissolved metals and sulphate across the tailingswater interface at the study site indicated a high degree of chemical stability. Solute concentrations in the water cover were homogeneous and generally low at all stations. Pore-water profiles revealed minor remobilization of some trace metals and radionuclides in the shallow pore water (~0.15 m).Key words: mine tailings, water cover, pore-water geochemistry, radium, metal mobility, diffusion, flux.
Experimental and theoretical study of the photochemical and thermal decomposition of maleic and dichloromaleic anhydrides
Authors: Ionescu A , Piétri N , Hillebrand M , Monnier M , Aycard J P
Published: July 2002

The photochemical and thermal behavior of maleic anhydride 1a and dichloromaleic anhydride 1b, in cryogenic matrix were investigated by means of FT-IR spectroscopy. The ketenylcarbenes represent the key intermediate in the decomposition processes of the anhydrides, even if they were not observed experimentally. The yields of the different products depend on the thermal or photochemical reaction conditions. The main photochemical products obtained from 1a were cyclopropenone and acetylene, whereas the major products from 1b were dichlorocyclopropenone and dichloroacetylene, along with small quantities of dichloropropadienone. The thermal reaction leads to dichloro propa dienone, CO, and CO2. MO calculations performed at the HF/6-31G*//HF/6-31G* level support the experimental mechanisms.Key words: photolysis, thermolysis, ab initio calculations, cryogenic matrix, ketenylcarbenes.
Localization of cells from the winter flounder gill expressing a skin type antifreeze protein gene
Authors: Murray Harry M , Hew Choy L , Kao Ken R , Fletcher Garth L
Published: July 2002

In situ hybridization on whole mounts and paraffin-sectioned winter flounder (Pleuronectes americanus) gill, using riboprobes specific to a skin type antifreeze protein (AFP) gene, showed a mRNA distribution associated with cells throughout the filament and the lamellae. Immunohistochemistry using antibodies for a skin-type AFP identified cells corresponding to those detected using in situ hybridization. Parallel experiments with antibodies for chloride-cell markers showed that these cells were not involved in antifreeze-protein expression. Similarly, goblet cells did not show cross-reactivity with the AFP antibodies. This general distribution suggested that pavement cells were likely involved. Reverse transcription polymerase chain reaction using gill cDNA templates and subsequent sequencing of the products confirmed the presence of skin type AFP transcripts in this tissue. Expression of a AFP in this area may act as a first line of defence against ice-crystal migration into peripheral tissues.
Experimental tests of intercohort competition for food and cover in the tidepool sculpin (Oligocottus maculosus Girard)
Authors: Szabo Andrew R
Published: July 2002

In the field, the tidepool sculpin, Oligocottus maculosus, has been observed to display a vertical intertidal distribution characterized by increasing mean standard length with decreasing distance above mean tidal height. It was hypothesized that this distribution is related to intercohort competition for food and (or) cover and, as a result, competi tive exclusion of smaller fish by larger fish from the lower pools. To test this hypothesis, several competition experiments were conducted that involved pairing O. maculosus from three size classes in a laboratory setting and observing their behaviour when presented with food or cover. When both fish attempted to procure food, the success rate of the larger fish was significantly higher than that of the smaller fish (Wilcoxon's signed-ranks test, T = 0, N = 6, p < 0.025). Furthermore, as the size difference between the two fish increased, the smaller fish made significantly fewer simultaneous attempts to procure the food (hierarchical log-linear test, partial χ2[5] = 28.326, p < 0.001), and utilized the cover significantly less (ANOVA, F[5] = 3.387, p = 0.008). The results from these experiments indicated that larger fish have a competitive advantage over smaller fish which extends to the acquisition of both food and cover. This is presumed to be the result of both greater competitive ability due to increasing size and an increased need for smaller fish to avoid detrimental aggressive interactions. In view of evidence from other papers indicating that the lower pools are more desirable to O. maculosus, it is suggested that intercohort competition is in part responsible for limiting the smaller fish to the upper tide pools.
MODELS AND ALGORITHMS FOR OPTICAL AND OPTOELECTRONIC PARALLEL COMPUTERS
Authors: SAHNI SARTAJ
Published: July 2002

This paper briefly reviews some of the more popular parallel-computer models-pipelined optical bus, optical transpose interconnect system (OTIS), and partitioned optical passive stars (POPS) network-that employ optical interconnect. The interconnect topology and some simple algorithms for each model are also described.
DRINFEL'D TWIST AND q-DEFORMING MAPS FOR LIE GROUP COVARIANT HEISENBERG ALGEBRAE
Authors: FIORE GAETANO
Published: July 2002

Any deformation of a Weyl or Clifford algebra can be realized through a change of generators in the undeformed algebra. q-deformations of Weyl or Clifford algebrae that were covariant under the action of a simple Lie algebra g are characterized by their being covariant under the action of the quantum group Uhg, q:=eh. We present a systematic procedure for determining all possible corresponding changes of generators, together with the corresponding realizations of the Uhg-action. The intriguing relation between g-invariants and Uhg-invariants suggests that these changes of generators might be employed to simplify the dynamics of some g-covariant quantum physical systems.
LATTICE GAS MODELS ON SELF-SIMILAR APERIODIC TILINGS
Authors: GEERSE C. P. M. , HOF A.
Published: July 2002

We discuss lattice gas models on the vertices of tilings in arbitrary dimension that are self-similar in the way Penrose tilings of the plane are self-similar. Among these, there are systems that fundamentally lack translation invariance. Under natural hypotheses on the interactions and the states, we prove the existence of thermodynaraic functions — the mean pressure, the mean energy and the mean entropy — and derive the variational principle. The relation between Gibbs states and tangent functionals to the mean pressure is investigated. Generalizations to quantum systems are also discussed. Our work extends results known for lattice gas models on periodic lattices.
EMERGENCE OF THE SIMULTANEOUS CONTINUOUS AND DISCRETE STRUCTURE OF THE ELECTROMAGNETIC FIELD
Authors: BACH ALEXANDER
Published: July 2002

We analyze a quantum central limit theorem without centering and a quantum Poisson limit theorem on an array of indistinguishable quanta and investigate the emergence of the continuous and discrete structure of the quantized electromagnetic field in classical states. Moreover, we identify the observables that converge to the random variables which induce the mixing measure of a classical state. Finally, we show that the transformation to normal order is a conditional expectation replacing expectations of functions of the annihilation and creation operator by expectations with respect to global classical observables of the array.
THE MEAN-FIELD THEORY OF DIRECTED POLYMERS IN RANDOM MEDIA AND SPIN GLASS MODELS
Authors: KOUKIOU F.
Published: July 2002

We give a unifying framework for the mean-field theory for models of spin glasses and directed polymers in a random medium defined on homogeneous graphs. Their phase diagram is studied in the complex plane of temperature.
HADAMARD STATES, ADIABATIC VACUA AND THE CONSTRUCTION OF PHYSICAL STATES FOR SCALAR QUANTUM FIELDS ON CURVED SPACETIME
Authors: JUNKER WOLFGANG
Published: July 2002

Quasifree states of a linear Klein-Gordon quantum field on globally hyperbolic spacetime manifolds are considered. After a short mathematical review techniques from the theory of pseudodifferential operators and wavefront sets on manifolds are used to develop a criterion for a state to be an Hadamard state. It is proven that ground- and KMS-states on certain static spacetimes and adiabatic vacuum states on Robertson-Walker spaces are Hadamard states. A counterexample is given which shows that the idea of instantaneous positive energy states w.r.t. a Cauchy surface does in general not yield physical states. Finally, the problem of constructing Hadamard states on arbitrary curved spacetimes is solved in principle.
FORMAL AND ANALYTIC RIGIDITY OF THE WITH ALGEBRA
Authors: GUERRINI LUCA
Published: July 2002

A family of deformations [Formula: see text] of the Witt algebra [Formula: see text] parametrized by the space ℰ of even polynomials with vanishing constant terms is defined. The existence of an isomorphism [Formula: see text], where [Formula: see text] refers to suitable completions of [Formula: see text], is proved. A relation between [Formula: see text] and Krichever–Novikov algebras of genus 0 and 1 is given.
VARIATIONAL PRINCIPLE AND THE DYNAMICAL ENTROPY OF SPACE TRANSLATION
Authors: MORIYA HAJIME
Published: July 2002

The dynamical entropy of space translations is used in the variational calculus of the pressure. It is shown that for quantum spin systems on a lattice of an arbitrary dimension, the pressure obtained in this way coincides with the usual one.
EXTENSION OF AUTOMORPHISMS OF A SUBFACTOR TO THE SYMMETRIC ENVELOPING ALGEBRA
Authors: MASUDA TOSHIHIKO
Published: July 2002

In this article, we consider an extension of automorphisms of a subfactor to the symmetric enveloping algebra introduced by Popa. We discuss the relation between this extension and invariants of automorphisms introduced by Kawahigashi. We also compute the symmetric enveloping algebras arising from orbifold subfactors.
SOME INEQUALITIES BETWEEN KNOT INVARIANTS
Authors: STOIMENOW ALEXANDER
Published: July 2002

We study the existence of relations between the degrees of the knot polynomials and some classical knot invariants, partially confirming and extending the question of Morton on the skein polynomial and a recent question of Ferrand.
A SYMMETRIC HIGH ORDER METHOD WITH MINIMAL PHASE-LAG FOR THE NUMERICAL SOLUTION OF THE SCHRÖDINGER EQUATION
Authors: SIMOS T. E. , AGUIAR JESUS VIGO
Published: July 2002

In this paper, a new high algebraic order symmetric eight-step method is introduced. For this method, a direct formula for the computation of the phase-lag is given. Based on this formula, an eight-step symmetric method with minimal phase-lag is developed. The new method has better stability properties than the classical one. Numerical illustrations on the radial Schrödinger equation indicate that the new method is more efficient than older ones.
FLAT HISTOGRAM METHOD OF WANG–LANDAU AND N-FOLD WAY
Authors: SCHULZ BEN JESKO , BINDER KURT , MÜLLER MARCUS
Published: July 2002

We present a method for estimating the density of states of a classical statistical model. The algorithm successfully combines the Wang–Landau flat histogram method with the N-fold way in order to improve the efficiency of the original single-spin-flip version. We test our implementation of the Wang–Landau method with the two-dimensional nearest neighbor Ising model for which we determine the tunneling time and the density of states on lattices with sizes up to 50 × 50. Furthermore, we show that our new algorithm performs correctly at right edges of an energy interval over which the density of states is computed. This removes a disadvantage of the original single-spin-flip Wang–Landau method where results showed systematically higher errors in the density of states at right boundaries. In order to demonstrate the improvements made, we compare our data with the detailed numerical tests presented in a study by Wang and Swendsen where the original Wang–Landau method was tested against various other methods, especially the transition matrix Monte Carlo method (TMMC). Finally, we apply our method to a thin Ising film of size 32 × 32 × 6 with antiparallel surface fields. With the density of states obtained from the simulations we calculate canonical averages related to the energy such as internal energy, Gibbs free energy and entropy, but we also sample microcanonical averages during simulations in order to determine canonical averages of the susceptibility, the order parameter and its fourth order cumulant. We compare our results with simulational data obtained from a conventional Monte Carlo algorithm.
EMPIRICAL REGULARITIES IN DISTRIBUTIONS OF INDIVIDUAL CONSUMPTION EXPENDITURE
Authors: HOHNISCH MARTIN , PITTNAUER SABINE , CHAKRABARTY MANISHA
Published: July 2002

We empirically investigate distributions of individual consumption expenditure for four commodity categories conditional on fixed income levels. The data stems from the Family Expenditure Survey carried out annually in the United Kingdom. We use graphical techniques to test for normality and lognormality of these distributions. While prevailing economic theory does not predict any structure for these distributions, we find that in at least three commodity categories individual consumption expenditure conditional on a fixed income level is lognormally distributed.
JAPANESE SUBSIDIARIES IN AUSTRALIA: WORK PRACTICES AND SUBCONTRACTING RELATIONS AS LEARNING MECHANISM
Authors: NICHOLAS STEPHEN , PURCELL WILLIAM
Published: July 2002

This paper tests whether Japanese subsidiaries in Australia were learning organisations. Two strands of MNE theory are presented: dynamic capability and organisational learning models. Japanese MNEs transferred both work and subcontracting practices to their Australian subsidiaries. Statistical tests showed that there were no significant deepening in work practices or subcontracting relationships between 1993 and 1997. Our tests also revealed no long-term learning, measured by changes in work practices and subcontracting relationships for firms who had operated in Australia for more than 10 and less than 10 years. The paper advances explanations of the absence of short-term and long-term learning.
SPACE–TIME DEPENDENT LAGRANGIANS AND WEAK–STRONG DUALITY: SINE-GORDON AND MASSIVE THIRRING MODELS
Authors: BHATTACHARYYA RAJSEKHAR , GANGOPADHYAY DEBASHIS
Published: July 2002

The formalism of space–time dependent Lagrangians developed in Ref. 1 is applied to the sine-Gordon and massive Thirring models. It is shown that the well-known equivalence of these models (in the context of weak–strong duality) can be understood in this approach from the same considerations as described in Ref. 1 for electromagnetic duality. A further new result is that all these can naturally be linked to the fact that the holographic principle has analogues at length scales much larger than quantum gravity. There is also the possibility of noncommuting coordinates residing on the boundaries.
THE FUZZY BAG MODEL REVISITED
Authors: PILOTTO F. , VASCONCELLOS C. A. Z. , COELHO H. T.
Published: July 2002

In this work we develop a new version of the fuzzy bag model. The new feature is the inclusion of energy–momentum conservation. This turns the model into a "real" bag model, as opposed to a relativistic potential model. One immediate consequence is that the bag constant B will acquire a radial dependence, B = B(r), whose functional form can be completely fixed without any arbitrariness. Such a feature is of importance in the study of neutron stars, where a radial dependence of B is usually put in by hand. The parameters of the model are found by fitting the masses of the baryon octet. We include center-of-mass, one-gluon exchange and pion exchange corrections for these masses.
QUARK MASS MATRICES IN THE A4 MODEL
Authors: MA ERNEST
Published: July 2002

If the standard model of quark interactions is supplemented by a discrete A4 symmetry (which may be relevant for the lepton sector), the spontaneous breaking of the electroweak gauge symmetry allows arbitrary quark masses, but all mixing angles are predicted to be zero. A pattern of the explicit breaking of A4 is proposed, which results in a realistic charged-current mixing matrix.
THE SU(n)-INVARIANT MASSIVE THIRRING MODEL WITH BOUNDARY REFLECTION
Authors: KOJIMA TAKEO
Published: July 2002

We study the SU (n)-invariant massive Thirring model with boundary reflection. Our approach is based on the free field approach. We construct the free field realizations of the boundary state and its dual. For an application of these realizations, we present integral representations for the form factors of the local operators.
ANOMALOUS INTERACTIONS OF FIVE-DIMENSIONAL USp(2k) GAUGE THEORY
Authors: ARAKANE Y. , ITOYAMA H.
Published: July 2002

We consider the five-dimensional USp (2k) gauge theory which consists of one antisymmetric and nf fundamental hypermultiplets. This gauge theory is a many-probe generalization of the SU(2) gauge theory in five dimensions considered by Seiberg in the context of probing type I superstring by a D4-brane. This gauge theory can also be obtained from the USp (2k) matrix model by matrix T-dual transformations in the large k limit.

We exhibit the anomalous interaction associated with this five-dimensional theory on the new phase, where the vacuum expectation values (vevs) of the scalars belonging to the antisymmetric hypermultiplet are also nonvanishing. On the Coulomb phase, the anomalous interaction has been computed in Refs. 1 and 2.
LOCALIZING GRAVITY ON A 3-BRANE IN HIGHER DIMENSIONS
Authors: GHERGHETTA TONY
Published: July 2002

We present metric solutions in six and higher dimensions with bulk cosmological constant, where gravity is localized on a 3-brane. The corrections to four-dimensional gravity from the bulk continuum modes are power-law suppressed. Furthermore, the introduction of a bulk "hedgehog" magnetic field leads to a regular geometry, and can localize gravity on the 3-brane with either positive, zero or negative bulk cosmological constant.
TYPE IIB ORIENTIFOLDS WITH DISCRETE TORSION
Authors: KARP ROBERT L. , PAUL ESPOSITO F. , WITTEN LOUIS
Published: July 2002

We consider compact four-dimensional ZN × ZM type IIB orientifolds, for certain values of N and M. We allow the additional feature of discrete torsion and discuss the modification of the consistency conditions arising from tadpole cancellation. We point out the differences between the cases with and without discrete torsion.
The CLEO III SILICON MICROVERTEX DETECTOR
Authors:   Representing CLEO Collaboration., LEE JIK
Published: July 2002

The upgrade of the CLEO detector has finished with the installation of the new silicon detector in February 2000. The detector is a four layer barrel-style device with double-sided silicon detectors. It spans the radial distance from 2.5 cm to 10.2 cm and cover 93% of the solid angle surrounding the interaction region. The innermost layer is 16 cm, the outermost is 55 cm long. Important features of the new design are a very small radiation length of the detector material and new front-end electronics to deal with the capacitive load of the long silicon wafer chains. First results of the detector performance will be presented.
The Silicon Pixel Sensors in ATLAS
Authors:   For the ATLAS Pixel Detector Collaboration., GOLELOV IGOR
Published: July 2002

The ATLAS experiment is now in the process of finalizing the development of the design of silicon pixel sensors for use in the pixel detector. The sensors will be operated in a severe LHC radiation enviroment with bias voltages at the end of lifetime up to 600 V while maintaining a good signal-to-noise ratio and charge collection efficiency, small cell size and minimal multiple scattering. The radiation hardness issues and quality assurance procedures are discussed.
THE UPGRADED LUMINOSITY SYSTEM FOR THE ZEUS EXPERIMENT
Authors:   On behalf of the ZEUS Collaboration, PAGANIS STATHES D.
Published: July 2002

A hybrid system consisting of a photon calorimeter, a magnetic spectrometer and an electron calorimeter designed to measure accurately the luminosity collected by the ZEUS detector after the HERA upgrade is presented.
THE PHENIX EXPERIMENT AT RHIC
Authors:   For the PHENIX Collaboration, HAGGERTY JOHN S.
Published: July 2002

The PHENIX experiment is one of two large detectors at Brookhaven's Relativistic Heavy Ion Collider. The detector that was operated in the first RHIC run in the summer of 2000 is described. Several million Au-Au collisions were recorded during the first run.
SUBDYNAMICS OF RELEVANT OBSERVABLES: A FIELD THEORETICAL APPROACH
Authors: LANZ LUDOVICO , VACCHINI BASSANO
Published: July 2002

An approach to the description of subdynamics inside the nonrelativistic quantum field theory is presented, in which the notions of relevant observable, time scale and complete positivity of the time evolution are stressed. A scattering theory derivation of the subdynamics of a microsystem interacting through collisions with a macrosystem is given, leading to a master equation expressed in terms of the operator-valued dynamic structure factor, a two-point correlation function which compactly takes the statistical mechanics properties of the macrosystem into account. For the case of a free quantum gas the dynamic structure factor can be exactly calculated and in the long wavelength limit a Fokker–Planck equation for the description of quantum dissipation and in particular quantum Brownian motion is obtained, where peculiar corrections due to quantum statistics can be put into evidence.
RECENT PROGRESS ON MODELS OF HIGHLY DISORDERED SUPERCONDUCTORS
Authors: TRIVEDI NANDINI , GHOSAL AMIT , RANDERIA MOHIT
Published: July 2002

We show, using a Bogoliubov-de Gennes (BdG) mean field theory, that the local pairing amplitude Δ(r) becomes highly inhomogeneous with increasing disorder in an s-wave superconductor. The probability distribution P(Δ) is peaked about the BCS value at low disorder, but with increasing disorder, progressively develops into a broad distribution with significant build up of weight near Δ≈0. At high disorder, the system is found to form superconducting "islands" separated by a non-superconducting sea. Surprisingly, a finite energy gap persists into the highly disordered state in spite of many sites having negligible pairing amplitude and is understood in detail within the BdG framework. Once the pairing amplitude becomes inhomogeneous, the role of quantum phase fluctuations becomes crucial in driving a superconductor-insulator transition at a critical disorder. The insulator is unusual as it has a finite gap for all disorder strengths in marked contrast to the Anderson insulator in non-interacting systems. We treat the phase fluctuations within a self consistent harmonic approximation and obtain the superfluid stiffness as a function of disorder, which agrees well with our earlier quantum Monte Carlo studies.
SPIN AND ORBITAL PHYSICS IN MANGANITES
Authors: GU R. Y. , WANG Z. D.
Published: July 2002

The spin and orbital physics in perovskite manganites is briefly reviewed. Perovskite manganites are well known as the materials exhibiting colossal magnetoresistance (CMR), whose mechanism is based on the double exchange (DE) interaction, in which the electron hopping is connected with the spin configurations of the manganite ions. Recent intensive studies have shown that this DE framework must be subjected to the strong correlation between orbital degenerate electrons. On one hand, the orbital degeneracy itself leads to an anisotropic DE hopping being different from the conventional DE, which in turn may result in the anisotropy of the magnetic structure, such as the A-type or the C-type antiferromagnetism. On the other hand, the electronic correlation between these degenerate electrons plays an important role in determining the phases of the system. The correlation can come from both the on-site Coulomb interaction and the Jahn–Teller coupling between the lattice distortion and the electrons. The interplay of the DE mechanism and the strong electronic correlation leads to various magnetic, orbital and/or charge ordering as well as the phase separation.
Susceptibility and Evidences of Charge Carriers Interaction above Tc in Nd1.85Ce0.15CuO4+δ
Authors: Lascialfari A. , Ghigna P. , De Gennaro S.
Published: July 2002

The charge carrier density plays a crucial role in the transition between normal and superconducting state in the copper-oxide superconductors. In Nd 1.85 Ce 0.15 CuO 4+δ sample, for charge carrier density n = nc≃ 0.07 the superconductivity sets in. In order to investigate the magnetic properties around nc, a set of magnetic susceptibility measurements in the temperature range 3-260K for samples with different charge carriers concentrations were realized. Magnetic susceptibility curves of Nd 1.85 Ce 0.15 CuO 4+δ revealed novel behavior well above the critical temperature T c: at fixed T ≥45 K , the susceptibility χ, reported as a function of the charge carrier density n, shows a peak around n=0.06 and drops to significantly lower values for n greater than 0.07, the value at which the samples become superconducting. The effective magnetic moment μeff shows the same behavior. The comparison of the present experimental results with recent transport ones gives evidence of a possible interaction between charge carriers above T c. The possibility that this effect could be due to a bipolarons-like mechanism of charge carriers interaction is discussed.
FIRST 13 YEARS OF HIGH-Tc: BRIEF REVIEW AND OPEN QUESTIONS
Authors: PAVUNA DAVOR
Published: July 2002

Exactly 13 years ago, in April 1986, appeared the famous paper1 by Bednorz and Müller, that announced a striking discovery of high-T c superconductivity in cuprates. Some 40'000 papers later, we are still struggling to understand the high-T c superconductivity. Here I summarize some of the most relevant recent results and open questions by discussing the observed phenomena in a rather complex electronic phase diagram of high-T c oxides.
PERSISTENT PHOTOCONDUCTIVITY IN La0.7CaxBa1-xMnO3 THIN FILMS
Authors: CAURO R. , GRENET J. C. , GILABERT A. , MEDICI M. G.
Published: July 2002

We report, for the first time, experiments of persistent photoconductivity (PPC) in thin films of manganese perovskites La 0.7 Ca 0.25 Ba 0.05 MnO 3 and La 0.7 Ca 0.2 Ba 0.1 MnO 3 showing a persistent decrease of a few percent of the resistance after illumination with visible light. These persistent photoinduced effects are seen only in a range of low temperatures (<25 K) well below the insulator-metal transition at respectively T c=173 K and T c=120 K. In this low temperature range, the transport mechanism is rather of activated hopping type regime.
LOW-FIELD MAGNETORESISTANCE ANISOTROPY IN STRAINED ULTRATHIN Pr0.67Sr0.33MnO3 FILMS
Authors: Wang H. S. , Li Qi
Published: July 2002

We have studied the anisotropic low-field magnetoresistance (LFMR)in ultrathin Pr 0.67 Sr 0.33 MnO 3(PSMO) films epitaxially grown on LaAlO 3(LAO), STiO 3(STO), and NdGaO 3(NGO)substrates which impose compressive, tensile, and nearly-zero strains in the films. The compressively-strained films show a very large negative LFMR in a perpendicular magnetic field and a much smaller MR in a parallel field, while the tensile-strain films show positive LFMR in a perpendicular field and negative MR in a parallel field. The results are interpreted based on the strain-induced magnetic anisotropy.
FORMATION OF CONDUCTIVE CdO THIN FILMS ON PHOTOCONDUCTIVE CdS THIN FILMS FOR WINDOW LAYER APPLICATIONS IN SOLAR CELLS
Authors: DAZA O. GOMEZ , REÁDIGOS A. ARIAS-CARBAJAL , CAMPOS J. , NAIR M. T. S. , NAIR P. K.
Published: July 2002

We report the formation of a thin layer of CdO on chemically deposited CdS thin films during air anneal at 370°C to 500°C for 5 min to 120 min. During a 5 min anneal, the sheet resistance of the CdS thin films drops from about 1013 □/9 to 3.5 k□/□(370°C) and 470 □/□(500°C). X-ray diffraction studies showed that this is associated with the formation of a thin layer of CdO layer, which occurs at temperatures above 370°C. The CdS, which remains under the conductive CdO top layer, is photosensitive - with photo-to-dark current ratio of 103 - 104. Essentially the air annealing converts the highly resistive and highly photosensitive intrinsic (i) CdS thin film into a (i)CdS-( n +)CdO layer. The technique offers prospects to convert the top part of a chemically deposited CdS thin film window layer of high photosensitivity, deposited on an absorber layer, to a conductive layer. This is of interest in thin film solar cell technology.
IMPROVED TWO-TERMINAL SILICON FUNCTIONAL OPTICAL SENSOR
Authors: MALIK A. , ACEVES M.
Published: July 2002

The modelling of two-terminal silicon-based multi-layered functional photosensor that operates at low-voltage bias is presented. The devices developed do not require external active electronic components (transistors, microminiature circuits, etc) to execute their functions. Neither to transform analogue input optical signals to digital output form that is very important for a wide range of optoelectronic applications.
EPR AND PHOTOPYROELECTRIC INVESTIGATIONS OFFe2O3-CaO-P2O5-SiO2GLASS AND GLASS-CERAMIC SYSTEMS
Authors: SIMON S. , ENIU D. , PASCA A. , DADARLAT D. , SIMON V.
Published: July 2002

Electron paramagnetic resonance (EPR) and standard photopyroelectric (PPE) measurements were carried out on 45(3.34 CaO · P2O5)(55 - x) SiO2· x Fe2O3glass and glass-ceramic samples with 0 ≤ x ≤ 30 mol% in order to obtain information on surrounding and magnetic interactions between iron ions introduced in CaO - P2O5- SiO2matrices and on the thermal diffusivity, α, of the investigated samples, respectively. The Fe3+-EPR data indicate that the size of ferromagnetic particles increases after heat treatment and their surroundings become more ordinated due to the partial crystallisation of samples. The room temperature values of the thermal diffusivity in the above-mentioned composition range are 0.41 × 10-6≤ α ≤ 2.33 × 10-6m2/ s . Vitroceramic samples obtained by heat treatment present a similar behaviour of the thermal diffusivity to that of the untreated samples. The temperature dependence α(T) in the range of interest (10–65°C) indicates a linear decrease of α with a slope of 10-8m2/ s/degree .
DEBYE TEMPERATURE OFMgB2
Authors: WEI Z. F. , CHE G. C. , WANG F. M. , WANG W. C. , HE M. , CHEN X. L.
Published: July 2002

In this study we determined the Debye temperature of MgB2powder by using the Rietveld refinement method based on the X-ray diffraction (XRD) data of this compound. MgB2 crystallizes with the AlB2structure, a space group of P6/mmm (191), and the lattice constants are a=b=3.0840 Å, c=3.5222 Å. The temperature factors of the atom Mg and B are 0.38 and 0.29 respectively, and the Debye temperature of MgB2is calculated to be 884 K at room temperature by Debye approximation.
SPECTROSCOPIC PROPERTIES OFB2O3–PbO–Nd2O3GLASSES
Authors: SIMON V. , ARDELEAN I. , MILEA I. , PETEANU M. , SIMON S.
Published: July 2002

Samples belonging to x Nd2O3(100-x) [ 2B2O3·PbO ] glass system, with 0≤ x≤ 40 mol%, are investigated by IR and UV–VIS spectroscopies in order to obtain evidence for the influence of Nd2O3on the local order from 2B2O3· PbO glass matrix. Besides the IR absorption bands characteristic to lead and boron arrangements, typical absorption lines of Nd3+ions around 4000 cm-1and 6000 cm-1are recorded. The 6000 cm-1band appears only for the samples with x≥25 mol% Nd2O3. The split of some UV–VIS absorption bands arising from transitions of neodymium ions in doublet lines as well as the shift of the absorption bands as the Nd2O3content increases denote the influence of the lead–borate matrix on the radiative transitions of the lanthanide ion.