bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Synthesis of Occidol
Authors: Mane Ramchandra Bhimrao , Kadam Abhijit Jaysingrao
Published: July 2002

Sodium borohydride reduction of 5,8-dimethyl-3,4-dihydronaphthalen-1-(2H)-one (4) yielded 5,8-dimethyl-1,2,3,4-tetrahydro-1-naphthol (5). The tetralol 5 on Vilsmeier-Haack reaction with N,N-dimethylacetamide yielded 1-(5,8-dimethyl-3,4-dihydro-2-naphthyl)ethan-1-one (7) which on hydrogenation over Pd/C afforded 1-(5,8-dimethyl-1,2,3,4-tetrahydro-2-naphthyl)ethan-1-one (8). The tetralol 5 on Vilsmeier-Haack formylation gave 5,8-dimethyl-3,4-dihydro-2-naphthaldehyde (9) which on reduction with lithium aluminium hydride followed by oxidation with the Jones reagent furnished 5,8-dimethyl-1,2,3,4-tetrahydro-2-naphthoic acid (11). The acid 11 on treatment with excess of methyllithium yielded (±)-occidol (1); with two moles of methyllithium it yielded ketone 8, which on reaction with methyllithium furnished (±)-occidol (1).
5-Aminofuro[3,2-c]pyridinium Tosylates and Substituted Furo[3,2-c]pyridine N-Oxides: Synthesis and Reactions
Authors: Bencková Mária , Krutošíková Alžbeta
Published: July 2002

5-Aminofuro[3,2-c]pyridinium tosylates 2a-2c were synthesized by direct N-amination of furo[3,2-c]pyridines 1a-1c with O-(4-methylbenzenesulfonyl)hydroxylamine in dichloromethane. Zwitterionic furo[3,2-c]pyridinium N-imides 3a-3c generated from 2a-2c and anhydrous potassium carbonate in N,N-dimethylformamide afforded by 1,3-dipolar cycloaddition reactions with dimethyl butynedioate or ethyl propiolate the corresponding furo[3,2-c]pyrazolo[1,5-a]pyridinecarboxylic esters 4a-4c and 5a-5c. Furo[3,2-c]pyridine N-oxides 6a-6c and their benzo derivative 6d were synthesized by reaction of 1 with 3-chloroperbenzoic acid in dichloromethane. Treatment of N-oxides 6 with benzoyl chloride and cyanide anion (Reissert-Henze reaction) was shown to produce the corresponding furo[3,2-c]pyridine-4-carbonitriles 7. In further transformations (acid and alkaline hydrolysis), the cyano group was converted successively to amide and carboxylic acid.
Complexes with New Chelate Anionic Ligands Formed by Nucleophilic Addition in Copper(II) Coordination Sphere. III. The Crystal Structures of (2,2'-Bipyridine-N,N')(cyanato-N)[methyl(2-cyano-2-imidoxy Ethaneimidate-N,N')]copper(II) and (2,2'-Bipyridine-N,N')(2-cyano-2-imidoxy Ethaneimidate-N,N')copper(II)
Authors: Dunaj-Jurčo Michal , Potočňák Ivan , Mikloš Dušan , Klement Robert
Published: July 2002

Crystal structures of Cu(II) compounds with new chelate anionic ligands are presented. The formulae of these compounds are [Cu(bipy)(mcoe)(NCO)] (1) and [Cu(bipy)(coe)] (2), where bipy is 2,2'-bipyridine, mcoe and coe are the anionic chelate ligands methyl(2-cyano-2-imidoxy ethaneimidate), [(ON)(NC)C-C(NH)(OCH3)]1- (3), and 2-cyano-2-imidoxy ethaneimidate, [(ON)(NC)C-C(NH)(O)]2- (4), respectively, formed by nucleophilic addition of methanol and hydroxide ion to the coordinatively activated β-carbon of the nitroso-dicyanomethanide. Formation of the hydroxide ion from water in the reaction mixture can be explained by protonation of the C(CN)3- anion. The coordination polyhedra in 1 and 2 are quite different. The coordination polyhedron around the Cu(II) ion in 1 is a distorted trigonal bipyramid and in 2 a distorted square. The Cu(II) ion in 1 is coordinated by four N atoms from two bidentate ligands and one N atom from the NCO- group. The crystal structure consists of discrete molecules with {CuN5} chromophore. On the other hand, the Cu(II) ion in 2 is coordinated by four N atoms from two bidentate ligands in square coordination and the molecules are linked by weaker contacts between copper and oxygen atoms (Cu-O1i = 2.503(3), Cu-O2ii = 2.801(3) Å; i = -x, -y, -z + 1; ii = -x + 1, -y, -z + 1) to infinite chains parallel with c. Thus the coordination polyhedron is completed to an elongated tetragonal bipyramid with the {CuN4O*O*} chromophore. The angle O1i-Cu-O2ii is 167.9(1)° and the crystal structure cannot be considered as molecular but consisting of chains running in one direction. Inspection of the bond distances in mcoe and coe indicates strongly delocalized π-bonding systems. This is also supported by the fact that the anions are almost planar with bond angles close to 120°. The calculated Wiberg (bond-order) indices show that due to conjugation, the bonds within the metallocycle in mcoe and coe exhibit partially multiple character.
A Hetero Diels-Alder Access to (Z)-Zeatin and (Z)-Isozeatin
Authors: Tolman Vladimír , Hanuš Jan , Sedmera Petr
Published: July 2002

(Z)-6-(4-Hydroxy-3-methylbut-2-en-1-ylamino)purine, (Z)-zeatin, and the isomeric (Z)-isozeatin, both free from the E isomers, were prepared using the cycloaddition of the in situ generated tert-butyl nitrosoformate on isoprene. A mixture of tert-butyl 5(and 4)-methyl-3,6-dihydro-2H-1,2-oxazine-2-carboxylates thus formed was deprotected and reductively cleaved to (Z)-4-amino-2(and 3)-methylbut-2-en-1-ols, which were chromatographically separated and finally alkylated with 6-chloropurine to give the title compounds.
Synthesis of Acyclic Nucleotide Analogues Derived from 2-Amino-6-C-substituted Purines via Cross-Coupling Reactions of 2-Amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-halopurines with Diverse Organometallic Reagents
Authors: Česnek Michal , Hocek Michal , Holý Antonín
Published: July 2002

Cross-coupling reactions of 2-amino-6-chloro-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}purine (1) and 2-amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-iodopurine (2) with diverse types of organometallic reagents have been studied. Arylboronic acids reacted with 1 to give the corresponding 2-amino-6-arylpurines 3a-3d in good yields. Analogously, trialkylaluminium reagents were used for the preparation of 6-alkyl-2-aminopurines 3k and 3l from 1. Hetarylzinc halides and hetarylstannanes required the use of 2-amino-6-iodopurine 2 to give the corresponding 2-amino-6-hetarylpurines 3e-3j in fair to good yields. A CuI/KF mediated coupling of perfluoroalkylsilanes with 2 afforded the 2-amino-6-perfluoroalkylpurines 3m and 3n in moderate yields. Cleavage of the esters 3 with bromo(trimethyl)silane gave the target free phosphonates 4 that were purified by ion- exchange chromatography. The title compounds were tested on antiviral and cytostatic activity.
An audit of activity and outcome from a daily and a weekly “one stop” rapid assessment chest pain clinic
Authors: Byrne J , Murdoch D , Morrison C , McMurray J
Published: July 2002

Objectives

The recent National Service Framework for coronary heart disease advocates the establishment of rapid assessment clinics for chest pain. But how should these clinics be organised and do they fulfil their objectives? The aim of this study was to compare referral patterns to a daily and a weekly “one stop” rapid access chest pain clinic (RACPC), and to examine clinical outcome in patients attending these clinics.

Design

Patients were prospectively categorised into one of the following subgroups: “acute coronary syndrome”, “stable coronary heart disease”, or “low risk/non-coronary chest pain”. Fatal and non-fatal outcomes were audited over eight months.

Setting

Both RACPCs were situated within the cardiology departments of two large Glasgow teaching hospitals. Patients were seen by a cardiologist, and underwent non-invasive testing.

Participants

A total of 633 patients with chest pain who were referred by their general practitioner; 500 came to the daily and 133 to the weekly clinic. Forty four (7%) were categorised as having an acute coronary syndrome, 267 (42%) as stable coronary artery disease, and 322 (51%) as low risk/non-coronary chest pain.

Results

Referral patterns to the two clinics differed significantly. Compared with the weekly clinic, more patients with an acute coronary syndrome (7.8 v 3.8%) and low risk/non-coronary chest pain (55.2 v 35.6%), but fewer patients with stable coronary disease (37.0 v 61.6%) were referred to the daily clinic (p<0.00001).

During follow up eight (1.3%) patients died from a cardiac cause, and eight (1.3%) patients suffered a myocardial infarction. None of these patients were classified as low risk/non-coronary chest pain.

Conclusions

(1) RACPCs do provide an effective tool for the early assessment of patients with possible angina. (2) The frequency with which clinics are scheduled may be an important factor in determining how the service is utilised in practice.
Human Rights Act 1998 and mental health legislation: implications for the management of mentally ill patients
Authors: Leung W-C
Published: July 2002

In the management of mentally ill patients, there is a tension between protecting the rights of individual patients and safeguarding public safety. The Human Rights Act 1998 emphasises on the former while two recent white papers focus on the latter.

This article first examines the extent to which the Mental Health Act 1983 is consistent with the Human Rights Act. It argues that while the recent white papers exploit the gaps in the judgments given by the European courts, its compatibility with human rights is very doubtful. The practical implications of the Human Rights Act for doctors are discussed.
Henry Currey FRIBA (1820–1900): leading Victorian hospital architect, and early exponent of the “pavilion principle”
Authors: Cook G C
Published: July 2002

The “pavilion plan” for hospital design originated in France in the 18th century and was popularised in England by John Roberton and George Godwin in the mid-19th century; the underlying rationale was that with improved ventilation the mortality rate (at that time exceedingly high) was significantly reduced. Among the enthusiasts for this new style, was Florence Nightingale (herself a miasmatist)—who had experienced astronomically high death rates in the hospital at Scutari during the Crimean War (1854–6). One of the leading exponents of this style of hospital architecture was Henry Currey (1820–1900) whose greatest achievement was undoubtedly the design for the new St Thomas’s Hospital on the Lambeth Palace Road.
Resolution of diabetic autonomic neuropathy
Authors: Burden M L , Burden A C
Published: July 2002

Many consider diabetic autonomic neuropathy to be an irreversible complication of diabetes of long duration. Three patients developed symptoms of autonomic neuropathy which subsequently resolved. Their autonomic neuropathy was not associated with long duration of diabetes, but with weight loss. Each had marked weight loss and resolution occurred on regaining remembered premorbid weight. A woman aged 20 was admitted with anorexia nervosa (weight loss 6 kg). She complained of feeling bloated. Gastroenterological investigations showed delayed gastric emptying. RR ratio (respiration and standing) was abnormal. Resolution occurred after two years. A male aged 18 developed diabetic symptoms, which were overlooked. Twelve months later he presented underweight and ketonuric; insulin treatment was started but within one month he became impotent. Resolution occurred after 18 months. An 80 year old man presented after six months trial of diet and sulphonylurea therapy. He was underweight, had ketonuria, and such muscle loss that he was unable to sit unaided. Insulin treatment was started. He developed severe symptomatic postural hypotension. This resolved six months later by which time he had regained his normal weight. These cases illustrated symptomatic autonomic neuropathy occurring in relation to weight loss with resolution on recovery of normal weight, a temporal pattern mimicking that of acute cachectic painful neuropathy. Treatment of autonomic neuropathy should be like that of cachectic neuropathy, that is with an expectation of recovery and should include strategies to regain premorbid weight and achieve glycaemic control
Citrus tristeza virus ultrastructure and associated cytopathology in Citrus sinensis and Citrus aurantifolia
Authors: Zhou Carol L. Ecale , Ammar El-Desouky , Sheta Hany , Kelley Sandra , Polek MaryLou , Ullman Diane E
Published: July 2002

Citrus tristeza virus ultrastructure and associated cytopathology was documented with three isolates and two hosts, sweet orange 'Madam vinous' (Citrus sinensis (L.) Osbeck) and Mexican lime (Citrus aurantifolia (L.) Swingle). Virions were long, flexuous, and disorganized or in swirled, parallel masses. Infection was common in phloem parenchyma and companion cells and less frequent in mature sieve elements. Immunogold labeling confirmed previous findings that the major coat protein encapsidated the length of purified virions, while the minor coat protein encapsidated one terminal. Three types of inclusions were observed: (i) viral arrays that reacted with antibodies against the major (p25) and minor (p27) Citrus tristeza virus coat proteins, (ii) fibrous inclusions that reacted with antibodies against the Citrus tristeza virus p20 gene product but were sparsely labeled with antibodies against either coat protein, and (iii) accumulated cytoplasmic vesicles associated with aggregated, vesiculating mitochondria. The latter resembled Beet yellows virus-like vesicles, which are typical of closterovirus infection, but did not react with any of our antibodies. Cytopathology did not differ between isolates and plant hosts. Most effects were observed in phloem parenchyma cells, including chloroplast degradation, mitochondria vesiculation, and nuclear membrane invagination. Multivesicular bodies and lipid-filled vesicles were abundant in the cytoplasm. Masses of electron-lucent vesicles and electron-dense bodies were present between the cell membrane and cell wall.Key words: immunolocalization, CTV major coat protein, CTV minor coat protein, CTV p20 gene product, inclusions, isolate severity.
Cell wall polysaccharides F1SS disclose the relatedness of the genus Geosmithia with Eupenicillium and Talaromyces
Authors: Prieto Alicia , Ahrazem Oussama , Gómez-Miranda Begoña , Bernabé Manuel , Leal J Antonio
Published: July 2002

Cell wall polysaccharides have been used as chemotaxonomic markers in a number of fungal genera. In this study, alkali-extractable and water-soluble cell wall polysaccharides F1SS were purified from cell walls of species of the genus Geosmithia. Chemical and 1H-NMR analyses of these polysaccharides revealed three different structures: (i) the polysaccharide from Geosmithia namylowskii was composed of β-(1[Formula: see text]5)-galactofuranose chains attached to an α-(1[Formula: see text]2)-(1[Formula: see text]6)-mannan core identical to that isolated in several species of Eupenicillium, (ii) the polysaccharide from Geosmithia viridis was a glucomannogalactan similar to that obtained in Talaromyces flavus, and (iii) the polysaccharide from Geosmithia putterillii contained β-(1[Formula: see text]5)-(1[Formula: see text]6)-galactofuranose with some units of the β-(1[Formula: see text]5) residues substituted at position O-6 by single residues of galactofuranose; this galactan was attached to an α-(1[Formula: see text]2)-(1[Formula: see text]6)-mannan core. The taxonomy of the genus is discussed according to the polysaccharides F1SS, and our results are compared with the results of rDNA analyses in this genus.Key words: Eurotiales, Geosmithia, Eupenicillium, Talaromyces, cell wall polysaccharides, chemotaxonomy.
Diurnal variation in bottom trawl survey catches: does it pay to adjust?
Authors: Hjellvik Vidar , Godø Olav Rune , Tjøstheim Dag
Published: July 2002

The diurnal bias of bottom trawl survey catches is studied with the purpose of adjusting for it and thereby improving the accuracy of abundance estimates. The correction term is estimated with uncertainty and thus increases the variance of the resulting abundance estimate. To investigate this adequately, we use a stochastic model describing diurnal fluctuations and examine the annual variation of the diurnal amplitude as a function of species and length. The diurnal amplitude is fairly stable for large fish, and for these, the bias-corrected estimate leads to a moderate increase in variance. For small fish, the diurnal amplitude is unstable, however, and the correction of diurnal bias occurs at the expense of a large increase in variance. This unstable amplitude also leads to a large year-to-year variation in catchability for small fish. For haddock (Melanogrammus aeglefinus), the diurnal amplitude depends heavily on fish length, indicating a strong decrease in catchability with decreasing fish length.
Chromatin remodeling and tissue-selective responses of nuclear hormone receptors
Authors: Hsiao Pei-Wen , Deroo Bonnie J , Archer Trevor K
Published: July 2002

Chromatin structure of eukaryotic genes regulates gene expression by controlling the accessibility of regulatory factors. To overcome the inhibitory nature of chromatin, protein complexes that modify higher order chromatin organization and histoneDNA contacts are critical players in regulating transcription. For example, nuclear hormone receptors regulate transcription by interacting with ATP-dependent chromatin-remodeling complexes and coactivators, which include histone acetyltransferases and histone methylases that modify the basic residues of histones. A growing number of tissue-specific nuclear hormone receptor ligands, termed "selective modulators", owe their specificity, at least in part, to the differential recruitment of these chromatin-modifying coactivators. The molecular mechanisms by which these compounds modulate the functions of nuclear hormone receptors are discussed here.Key words: chromatin, BRG1, SWISNF, nuclear receptor, glucorticoid receptor, transcription, MMTV.
Heavy metal transport in soil contaminated by residual light non-aqueous phase liquids (LNAPLs)
Authors: Dubé Jean-Sébastien , Galvez-Cloutier Rosa , Winiarski Thierry
Published: July 2002

This paper presents an experimental study on mixed soil contamination, more specifically on heavy metal behaviour in soil contaminated by residual non-aqueous phase liquids (NAPLs). Remediation of mixed contaminated sites is a complex technical goal because of the presence of physically and chemically different contaminants and potential interactions between them. Commonly encountered contaminants in mixed contaminated soils include light and dense organic liquids (LNAPLs, DNAPLs) and heavy metals. This study investigated interactions between three residual LNAPLs and three heavy metals (Cd, Cu, Pb) in a carbonated soil. The objectives of the study were to (i) establish the presence of interactive processes in the behaviour of the contaminants, with a focus on the influence of residual LNAPL on heavy metal transport and retention; and (ii) determine the nature of these interactions. Results showed that the LNAPL having the highest residual saturation enhanced heavy metal mobility and decreased heavy metal retention by the soil. On the other hand, the geochemical distribution of heavy metals was not significantly modified by chemical interactions with the residual LNAPLs. Specific modifications of Pb and Cu geochemical distributions rather appeared to be the result of modifications of soil hydrodynamics by residual LNAPL.Key words: contaminated soil, mixed contamination, heavy metals, LNAPL, preferential flow, contaminant mobility.
Relationship of root rot to black spruce windfall and mortality following strip clear-cutting
Authors: Whitney R D , Fleming R L , Zhou K , Mossa D S
Published: July 2002

Root and butt rots are often implicated as causal factors influencing windfall and mortality of residual trees following partial cutting. Measurements of decay at stump level (i.e., the upward extension of root rot) were made on cross-sectional discs taken from windfallen and standing dead 100- to 130-year-old black spruce (Picea mariana (Mill.) BSP) near Nipigon in northwestern Ontario. Subsequently, causal fungi were identified using laboratory culturing procedures. The incidence and amount of decay in windfallen trees within leave strips following alternate strip clear-cutting was higher than the general stand levels but lower than that found in windfallen trees in uncut forest. The incidence and amount of decay was also higher in windfallen trees near the centres of the leave strips than in those near the edges and corners of these strips. These results indicate a strong association between root rot and windfall and suggest that for comparable windfirmness, trees near the edges of residual stands must have less decay than those in more sheltered locations. Decay levels tended to be lower on poorly drained sites than on well-drained sites. In uncut forest, and especially in the leave strips, more trees were uprooted than died standing or suffered stem breakage. The incidence and amount of decay tended to be lower in uprooted trees than in standing dead trees or those with stem breakage, although in uncut forest virtually all windfallen or standing dead trees had some degree of stump-level decay. Of the 21 wood-rotting Basidiomycetes isolated from windfallen and standing dead trees, Inonotus tomentosus (Fr.:Fr.) Teng was the most frequent, followed in order by Armillaria ostoyae (Romagn.) Herink, Coniophora puteana (Schum.:Fr.) Karst., and Scytinostroma galactinum (Fr.) Donk. The incidence of I. tomentosus, C. puteana, Xeromphalina campanella (Batsch.:Fr.) Kuhner & Maire, and Serpula himantioides (Fr.:Fr.) Karst., but not Armillaria ostoyae, Scytinostroma galactinum, and Sistotrema brinkmanii (Bres.) Erik., was greater in windfallen and standing dead trees from the leave strips than in the general stand populations. In the leave strips, I. tomentosus, Amylostereum chailletii (Pers.:Fr.) Boid., and Trichaptum abietinum (Dickson:Fr.) Ryv. tended to greater relative abundance in standing dead trees, while the relative abundance of C. puteana and Serpula himantioides was greater in trees with stem breakage. Armillaria ostoyae and Scytinostroma galactinum were as abundant in uprooted trees as in standing dead trees or those with stem breakage. Ascocoryne sarcoides (Jacq.:Fr.) G. & W., a staining fungus that may protect against decay fungi, was frequently isolated in this study.
Asynchronous maturation of the sexes may limit close inbreeding in a subsocial spider
Authors: Bukowski Todd C , Avilés Leticia
Published: July 2002

We studied the temporal patterns of maturation and sexual receptivity of a subsocial spider, Anelosimus cf. jucundus, in southern Arizona. In subsocial spiders, sibling males and females share a common nest for a large portion of their life cycle, often only dispersing short distances close to the mating season. We found that, on average, male A. cf. jucundus matured 9 days earlier than females and that females did not become sexually receptive until 10 days following their final molt to maturity. The periods of sexual receptivity of sibling males and females, therefore, would be separated in time by a significant fraction of an adult male's life cycle. We also found significant asynchrony in maturation dates across nests and nest clusters at the two collection localities. We suggest that these temporal patterns may limit the opportunities for sibling males and females to mate with each other, thus explaining the apparent absence of mechanisms to discriminate against kin as mates in this species.
Grouping patterns, reproduction, and dispersal in a population of sitatungas (Tragelaphus spekei gratus)
Authors: Magliocca Florence , Quérouil Sophie , Gautier-Hion Annie
Published: July 2002

A population of sitatungas (Tragelaphus spekei gratus) living in a forest swamp clearing, Maya Nord, in the Republic of Congo was studied over 3½ years and its grouping patterns and population dynamics were analysed. The sitatungas in this clearing formed a stable group, which remained in residence. The group (1636 individuals) functioned like a harem. As a result of intrasexual competition, all the males and some of the females born at Maya left the group before reaching sexual maturity. We hypothesize that this large grouping resulted from the development of a tendency for females to be gregarious for reasons related to food availability. This tendency, combined with an aseasonal pattern of reproduction, favours direct monopolization of females by one male. Social and mating strategies observed at Maya fit the model of "female-defence polygyny" (Emlen and Oring). Our results provide an argument in favour of relating food availability and grouping patterns, and underline the plasticity of social organization and mating strategies in sitatungas.
HAIRPIN LANGUAGES
Authors: PĂUN GHEORGHE , ROZENBERG GRZEGORZ , YOKOMORI TAKASHI
Published: July 2002

Molecules with hairpin structure(s) form a natural extension of linear non-branched molecules, and they have been already used in experimental work in DNA computing. In this paper we introduce and investigate classes of string languages (hence languages modeling the sets of linear DNA molecules), consisting of strings which can (fold on itself and) form hairpins. We classify the complexity of these classes using language-theoretic techniques. We also discuss a further use of hairpin molecules in DNA computing.
ABSENCE OF TRANSPORT IN ANDERSON LOCALIZATION
Authors: NAKANO FUMIHIKO
Published: July 2002

We consider the charge transport in the tight-binding Anderson model. Under a mild condition on the Fermi projection, we show that it is zero almost surely. This result has wider applicability than our previous work [12], while the definition of charge transport is slightly different. It also applies to the computation of non-diagonal component of the conductivity tensor which recovers the famous result of quantization of Hall conductivity in quantum Hall systems.
Schrödinger Operators with Fairly Arbitrary Spectral Features
Authors: Krishna M. , Sunder V. S.
Published: July 2002

It is shown, using methods of inverse-spectral theory, that there exist Schrödinger operators on the line with fairly general spectral features. Thus, for instance, it follows from the main theorem, that if Σ is any perfect subset of (-∞, 0], then there exist potentials qj, j = 1, 2 such that the associated Schrödinger operators Hj are self-adjoint and satisfy: σ(Hj)=Σ∪[0, ∞), σ ac (Hj)=[0, ∞), σ pp (H1)=σ sc (H2) =Σ. The main result also implies the existence of states with interesting transport properties.
Quantum Affine Toda Solitons
Authors: Mackay N. J.
Published: July 2002

We review some of the progress in affine Toda field theories in recent years, explain why known dualities cannot easily be extended, and make some suggestions for what should be sought instead.
GEOMETRY OF MODULI SPACES OF FLAT BUNDLES ON PUNCTURED SURFACES
Authors: FOTH PHILIP A.
Published: July 2002

For a Riemann surface with one puncture we consider moduli spaces of flat connections such that the monodromy transformation around the puncture belongs to a given conjugacy class with the property that a product of its distinct eigenvalues is not equal to 1 unless we take all of them. We prove that these moduli spaces are smooth and their natural closures are normal with rational singularities.
SIMULATING TRAFFIC ON GERMAN HIGHWAYS BASED ON THE NAGEL–SCHRECKENBERG-MODEL
Authors: EBERSBACH ANJA , SCHNEIDER JOHANNES , MORGENSTERN INGO
Published: July 2002

The Nagel–Schreckenberg model (NaSch model) proved to be a realistic approach to describe traffic flow on single-lane streets. In this paper, we add some lane changing rules for two-lane traffic and discuss the influence of the variation on the mean velocity and the flow.
FIVE-DIMENSIONAL CHERN–SIMONS GRAVITY WITH NONLINEAR ELECTRODYNAMICS
Authors: MACÍAS ALFREDO , LOZANO ENRIQUE
Published: July 2002

We consider five-dimensional theory of gravity proposed recently by Chamseddine. It is based on the Chern–Simons five-form and the SO(1,5) gauge group. The action naturally contains a Gauss–Bonnet term, an Einstein term and a cosmological constant. We shall see that by imposing to this action the five-dimensional principal fiber bundle structure and the toroidal dimensional reduction process, the resulting U(1) gauge theory contains non-minimal couplings to gravity and nonlinear modifications to the standard Einstein–Maxwell–dilaton theory.
ON THE STATISTICAL ORIGIN OF TOPOLOGICAL SYMMETRIES
Authors: SAMANI K. AGHABABAEI , MOSTAFAZADEH A.
Published: July 2002

We investigate a quantum system possessing a parasupersymmetry of order 2, an orthosupersymmetry of order p, a fractional supersymmetry of order p+1, and topological symmetries of type (1,p) and (1,1,…,1). We obtain the corresponding symmetry generators, explore their relationship, and show that they may be expressed in terms of the creation and annihilation operators for an ordinary boson and orthofermions of order p. We give a realization of parafermions of order 2 using orthofermions of arbitrary order p, discuss a p=2 parasupersymmetry between p = 2 parafermions and parabosons of arbitrary order, and show that every orthosupersymmetric system possesses topological symmetries. We also reveal a correspondence between the orthosupersymmetry of order p and the fractional supersymmetry of order p+1.
FLOW EQUATIONS FOR HAMILTONIANS
Authors: WEGNER FRANZ J.
Published: July 2002

A method to diagonalize or block-diagonalize Hamiltonians by means of an appropriate continuous unitary transformation is reviewed. We will outline (i) the procedure for the elimination of the electron-phonon interaction and the construction of the effective attractive electron-electron interaction, and (ii) the application to some systems with electron-electron interaction (n-orbital model and Hubbard model).
AN EXACT RENORMALIZATION GROUP APPROACH TO FRUSTRATED MAGNETS
Authors: TISSIER M. , DELAMOTTE B. , MOUHANNA D.
Published: July 2002

Frustrated magnets are a notorious example where usual perturbative methods fail. Having recourse to an exact renormalization group approach, one gets a coherent picture of the physics of Heisenberg frustrated magnets everywhere between d=2 and d=4: all known perturbative results are recovered in a single framework, their apparent conflict is explained while the description of the phase transition in d=3 is found to be in good agreement with the experimental context.
A PROTOTYPE TRACK-FINDING PROCESSOR FOR THE LEVEL-1 TRIGGER OF THE CMS ENDCAP MUON SYSTEM
Authors: WANG S. M. , ACOSTA D. , MADORSKY A. , SCURLOCK B. , ATAMANCHUK A. , GOLOVTSOV V. , RAZMYSLOVICH B.
Published: July 2002

We report on the development and performance of a novel track-finding processor for the Level-1 trigger of the CMS endcap muon system. The processor links track segments identified in the cathode-strip chambers of the endcap muon system into complete three-dimensional tracks. It then measures the momentum of the best track candidates from the sagitta measured between three muon chambers in the endcap fringe field. The processor is pipelined at 40 MHz, and has an overall latency of 400 ns. The logic for the prototype is implemented in high-density FPGAs and SRAM memory. It receives approximately 3 gigabytes of data every second from a custom backplane operating at 280 MHz. Test results of the prototype are consistent with expectation.
CONSTRAINTS ON FORCES INSPRIRED BY EXTRA DIMENSIONAL PHYSICS FOLLOWING FROM THE CASIMIR EFFECT
Authors: MOSTEPANENKO V. M.
Published: July 2002

We consider Yukawa-type forces inspired by extra dimensional physics and by exchange of light elementary particles. Constraints on these forces following from the recent measurements of the Casimir force are analysed. We show that the experiments with the Casimir force gave the possibility to strengthen the previously known constraints up to several thousand times in a wide interaction range. Further strengthening is expected in near future.
ON THE DISPERSIVE VAN DER WAALS FORCES
Authors: FARINA C. , SANTOS F. C. , TORT A. C.
Published: July 2002

We compute the non-retarded dispersive force between an electrically polarizable atom and a magnetically polarizable one. We show, in agreement with Feinberg and Sucher's result, that while the retarded force is proportional to 1/r8, the non-retarded one is proportional to 1/r5. We give a physical interpretation for this rather unexpected result.
MAGNETISM, PHONONS AND ANISOTROPY OF HIGH TEMPERATURE CUPRATES SUPERCONDUCTORS
Authors: FRIEDEL JACQUES , KOHMOTO MAHITO
Published: July 2002

Phonon or electron mediated weak BCS attraction is enough to have high critical temperature if a van Hove anomaly is at work. This could apply to electron doped compounds and also to compounds with CuO 2 planes overdoped in holes, where T c decreases with increasing doping. If phonons dominate, it should lead to an anisotropic but mainly s superconductive gap, as observed recently in overdoped LaSrCuO, and probably also in electron doped compounds. If electrons dominate, a d-gap should develop as observed in a number of cases. In the underdoped range, the observed decrease of T c with hole doping can be related in all cases to the development of antiferromagnetic fluctuations which produces a magnetic pseudogap, thus lowering the density of states at the Fermi level. The observed mainly d-superconductive gap then can be due to a prevalent superconductive coupling through antiferromagnetic fluctuations; it could also possibly be attributed to the same phonon coupling as in the overdoped range, now acting on Bloch functions scattered in the magnetic pseudogap. More systematic studies of superconductive gap anisotropy and of magnetic fluctuations would be in order.
ANTIFERROMAGNETIC PHASE OF WIGNER ELECTRON CRYSTAL
Authors: RAJESWARAPALANICHAMY R. , IYAKUTTI K.
Published: July 2002

The ground state energies of the 3-dimensional antiferromagnetic Wigner crystal corresponding to sc, bcc, fcc, diamond and perovskite structures are computed and the structural stability is analyzed. It is found that the bcc structure has the lowest energy. The possibility of the antiferromagnetic phase of the Wigner crystal having cubic or spherical surface as the region of occupation is analyzed. The effect of correlation is suitably taken into account. This still lowers the ground state energy. The calculations are done for the whole range of the density parameter r s from 1 to 200. The low density region favorable for Wigner crystallization is found to be above r s =10. The structure dependent Wannier function is approximated by orthonormalized Gaussian and it is employed in the calculation. The orbital exponent of the Gaussian is used as a variational parameter. The calculations are also done for the non-uniform positive background case.
QUANTUM HALL STRIPES: CHERN–SIMONS THEORY AND ORIENTATIONAL MECHANISMS
Authors: ROSENOW BERND , SCHEIDL STEFAN
Published: July 2002

We develop a bosonic Chern–Simons theory to describe a two-dimensional electron gas in intermediate magnetic fields. Within this approach, inhomogeneous states emerge in analogy to the intermediate state of a superconductor. At half filling of the highest Landau level we find unidirectional charge-density-wave (CDW) solutions. With a semiclassical calculation we give an intuitive explanation of the change of CDW orientation in the presence of an in-plane magnetic field. An anisotropy in the electron band mass is suggested as a possible source of the reproducible orientation of the CDW.
BOSE CONDENSATION IN A RESTRICTED GEOMETRY
Authors: BONINSEGNI MASSIMO
Published: July 2002

A theoretical investigation is carried out of the ground state of a finite assembly of Hose hard spheres enclosed in a spherical cavity. Total and condensate radial densities are computed, and the non-uniform condensate is studied as a function of the number of particles in the cavity. Comparison with mean-field results is made. Possible experimental implications are discussed.
MAGNETISM AND SUPERCONDUCTIVITY IN NANOSTRUCTURED Nb-Dy SYSTEMS
Authors: O'Shea M. J. , Jiang H.
Published: July 2002

We have prepared Nb/Dy/Nb trilayers to study size effects on the magnetic and superconductor properties and to look at the influence of the magnetic layer on a superconductor layer in a nanoscale system. We find size effects on the magnetic properties of the Dy layer for thickness less than 10 nm and size effects associated with the superconductor layer for Nb layers of thickness less than 50 nm. In addition increasing the thickness the Dy layer reduces the superconductor transition temperature of the Nb layer.
GENERAL FORM OF SUPERUNIVERSALITY FOR FRACTAL DIMENSIONS IN ONE-DIMENSIONAL MAPS
Authors: CAO KE-FEI , ZHOU ZHONG , GAO WEN , PENG SHOU-LI
Published: July 2002

In one-dimensional continuous maps, there is an internal relationship between equivalent scaling factors αe and fractal dimensions d of Feigenbaum-type attractors on all critical (accumulation) points of transitions to chaos. In general, for m-modal maps with m turning points C1,C2,…,Cm, by defining αe as the geometric average of all scaling factors αCi(i=1,2,…,m), |αe| =|αC1 αC2… αCm|1/m, the superuniversal relationship d(W) log |W| |αe(W)|=β(e) holds, where |W| is the basic period of the m-tuply superstable sequences W, and β(e) is not only independent of the concrete sequences W, but also independent of the concrete maps. This is a general superuniversality for arbitrary multimodal maps, which is verified numerically for the cases of m ≤ 3 and can also be extended to Lorenz maps with a discontinuous point.
Comparison studies of spiral growth mechanism in Bi2Sr2CaCu2Oy and YBa2Cu3Oy high temperature superconducting single crystals
Authors: Wang X. L. , Liu H. K. , Dou S. X.
Published: July 2002

The spiral growth mechanisms associated with the growth conditions of Bi 2 Sr 2 CaCu 2 O y (Bi-2212) crystals grown at a KCI surface have been studied. The spiral growth mechanisms and the effects of growth conditions on the formation of spirals in YBa 2 Cu 3 O y (Y-123) thin films and single crystal have also been studied. Screw dislocation formation mechanism in the Bi2212 is different from that in Y-123. A model for a "vapour" deposition process with discontinuous growth conditions is put forward. It is proposed that spiral growth in Bi-2212 is similar to that in Y-123 thin films produced by Pulsed Laser Deposition. It is concluded that the formation of screw dislocations and discontinuous growth conditions are responsible for the coexistence between spiral and two-dimensional nucleation growth.
OPTICAL CONDUCTIVITY OF ONE-DIMENSIONAL NARROW-GAP SEMICONDUCTORS
Authors: LEE HYUN C.
Published: July 2002

The optical conductivities of two one-dimensional narrow-gap semiconductors, anticrossing quantum Hall edge states and carbon nanotubes, are studied using bosonization method. A lowest order renormalization group analysis indicates that the bare band gap can be treated perturbatively at high frequency/temperature. At very low energy scale the optical conductivity is dominated by the excitonic contribution, while at temperature higher than a crossover temperature the excitonic features are eliminated by thermal fluctuations. In case of carbon nanotubes the crossover temperature scale is estimated to be 300 K.
MAGNETIC FIELD DEPENDENCE OF THE MICROWAVE SURFACE RESISTANCE IN MgB2 SUPERCONDUCTORS
Authors: AGLIOLO GALLITTO A. , FRICANO S. , LI VIGNI M. , KOLESNIKOV N. N. , KULAKOV M. P.
Published: July 2002

We report experimental results on microwave surface resistance in MgB2 superconductors. The results have been obtained using the cavity perturbation method. Two samples have been investigated: one was made up of commercial Alfa-Aesar powder and the other one was obtained by direct reaction from elements. The temperature and dc magnetic field dependence of the surface resistance has been investigated down to 4.2 K and up to 10 kOe, respectively. Our results show that microwave losses are strongly affected by the magnetic field even by a relatively weak one. In particular, an unusually enhanced field dependence of the low-T residual surface resistance has been detected in both samples.
STAR-TRIANGLE EQUATIONS AND IDENTITIES IN HYPERGEOMETRIC SERIES
Authors: AU-YANG HELEN , PERK JACQUES H. H.
Published: July 2002

In this paper, we introduce the cyclic basic hypergeometric series p + 1Φp with q → ω where ωN = 1. This is a terminating series with N terms, whose summand has period N. We show how the Fourier transform of the weights of the integrable chiral Potts model are related to the 2Φ1, which is summable. We show that 3Φ2 satisfies certain transformation formulae. We then show that the Saalschützian 4Φ3 series is summable at argument z = ω. This then gives the simplest proof of the star-triangle relation in the chiral Potts model. Finally, we let N → ∞, where the star-triangle equation becomes a two-sided identity for the hypergeometric series.
ELECTRON DENSITY FUNCTIONAL THEORY
Authors: DOBSON J. F.
Published: July 2002

A brief summary is given of electronic density functional theory, including recent developments: generalized gradient methods, hybrid functionals, time dependent density functionals and excited states, van der Waals energy functionals.
QUANTIZED VORTICES IN SUPERFLUIDS AND SUPERCONDUCTORS
Authors: THOULESS D. J. , AO PING , NIU QIAN , GELLER M. R. , WEXLER C.
Published: July 2002

We give a general review of recent developments in the theory of vortices in superfluids and superconductors, discussing why the dynamics of vortices is important, and why some key results are still controversial. We discuss work that we have done on the dynamics of quantized vortices in a superfluid. Despite the fact that this problem has been recognized as important for forty years, there is still a lot of controversy about the forces on and masses of quantized vortices. We think that one can get unambiguous answers by considering a broken symmetry state that consists of one vortex in an infinite ideal system. We argue for a Magnus force that is proportional to the superfluid density, and we find that the effective mass density of a vortex in a neutral superfluid is divergent at low frequencies. We have generalized some of the results for a neutral superfluid to a charged system.
EFFECTIVE ORBITAL INTERACTION: SPIN AND ORBITAL ORDERING IN UNDOPED MANGANITES
Authors: SHENG L. , SHENG D. N.
Published: July 2002

Including strong on-site interorbital Coulomb interaction and Jahn–Teller (J-T) coupling, we derive an effective spin and orbital (isospin) interaction from the two-band double-exchange model by using projection operator method. For the resulting Hamiltonian, anisotropic A-type antiferromagnetic (A-AF) state emerges naturally from a simple mean-field approximation in certain parameter region. We predict that the alternatingly occupied eg orbitals in the A-AF state should be (d3z2-r2-dx2-y2)/(d3z2-r2+dx2-y2) not d3x2-r2/d3y2-r2 as suggested in some other works. These results are in good agreement with experimental observations in undoped manganites. More accurate Monte Carlo simulations are performed to verify the mean-field ground-state phase diagram and study the finite-temperature spin and isospin disordering phase transitions. The main effect of the J-T coupling is to alter the effective coupling strength, quantitatively.
AN APPROACH TO UNIFYING CLASSICAL AND QUANTUM ELECTRODYNAMICS
Authors: AUCI MASSIMO , DEMATTEIS GUIDO
Published: July 2002

The foundations of quantum mechanics (QM) can find a consistent and exhaustive explanation in a new theoretical context. The "Approach" allows us to justify both classical and quantum electromagnetic phenomenology by using classical concepts. In this paper we review the bases of the attempt originating form the role that the transverse component of the Poynting vector plays in localising energy in the neighbourhood of an electromagnetic source and we analyse the quantum implications.
ELECTRONIC PROPERTIES OF COPPER-3d TRANSITION-METAL PAIRS IN SILICON
Authors: JUSTO JOÃO F. , ASSALI LUCY V. C.
Published: July 2002

We report a theoretical investigation of the chemical trends in the electronic properties of the substitutional Cu-interstitial 3d-transition-metal (Cr, Mn, Fe) trigonal pairs in silicon. The calculations were carried out in the framework of the multiple-scattering X α molecular cluster model. The electronic structures show that the stability of these pairs is mostly the result of a covalent interaction between the molecular orbitals coming not only from the Cu and TM atoms but also from the neighboring Si atoms. These results are in contrast to an ionic model which has been generally invoked to explain the stability of those pairs, but in agreement with some recent experimental findings. The Fermi contact terms for all the stable pairs in different charge states were computed and compared to available experimental data. We speculate on the existence of a different microscopic structure to explain these Cu-related complex pairs.
A SIMPLE NEURAL NETWORK APPROACH TO INVARIANT IMAGE RECOGNITION
Authors: ANDRECUT M. , ALI M. K.
Published: July 2002

In this paper we propose a simple neural network architecture for invariant image recognition. The proposed neural network architecture contains three specialized modules. The neurons from the first module are connected in a cellular neural network structure, which is responsible for image processing: edge detection and segmentation. The second module is a feed forward neural network for invariant feature extraction from the sensorial layer: computation of the pair distribution function and bond angle distribution function. The third module is responsible for image classification. An application to the face recognition problem is also presented.
CHEMICAL BATH DEPOSITION: A PROMISING TECHNOLOGY TO BUILD LOW COST SOLAR CELLS
Authors: NUÑEZ A. , NAIR P. K. , NAIR M. T. S.
Published: July 2002

Following the model of DeVos and Pauwels (1981), we calculated the spectral factor of efficiencies (η1) for n +-p or n +-i-p heterojunctions that can be formed by different thin absorber materials (p-type or intrinsic(i)) with n +-type CdS thin films produced by conversion of chemically deposited CdS thin films by doping with Cl or In as reported before. The materials with η1 comparable to that of CuInSe 2 (Eg, 1.01 eV: 57%) are AgBiS 2 (Eg, 0.9 eV: 56%), Cu 2 SnS 3 (Eg, 0.91 eV: 57%), PbSnS 3 (Eg, 1.05 eV: 57%), PbSbS 4 (Eg, 1.13 eV: 56%).
Room Temperature Photoluminescence of TiO2 Thin Films Doped with Tb
Authors: Conde-Gallardo A. , García-Rocha M. , Calderón I. Hernández , Palomino-Merino R.
Published: July 2002

Results on the fabrication and characterisation of thin films of the novel host, titania ( TiO 2), for the Tb 3+ activator ion are reported. The titania films were produced by the sol-gel process at room temperature using the dip coating method and deposited on silicon and corning glass substrates. It is shown that a different surface morphology is developed for the TiO 2:Tb films deposited on different substrates. When enough amount of Tb is incorporated and, a He-Cd 325 nm photoexcitation is used as excitation line, the films show green photoluminescence (PL) signal associated with the 5 D 4→7 F j transition of the electronic structure of Tb 3+ plus an broad band due to matrix's defects. The PL emission has better characteristics for the films deposited on silicon wafers.
Synthesis and Electrical Properties of SmBi5Fe2Ti3O18
Authors: Prasad N. V. , Prasad G. , Bhimasankaram T. , Suryanarayana S. V. , Kumar G. S.
Published: July 2002

SmBi 5 Fe 2 Ti 3 O 18, a five layered bismuth oxide compound is synthesized using a solid-state double sintering method. DC conductivity, impedance, and AC conductivity are studied in the temperature range 30–500°C and frequency range 1 kHz–1 MHz. Complex impedance plots are used to separate grain and grain boundary contributions to electrical impedance. Activation energy for DC conductivity was found to be around 1.0 eV. The results are analyzed to understand the conductivity mechanism.
Friction on a Quantized Vortex in a Superfluid
Authors: Zhu X.-M. , Ao P.
Published: July 2002

We obtain the explicit expression of the friction on a moving quantized vortex, following the formulation of Thouless, Ao and Niu. It is shown that the friction on a moving vortex is sensitive to details but does not change the transverse force. We provide a general thermodynamic interpretation for the mutual independence of the transverse force and the friction. The friction is evaluated for the case of quasiparticle contributions in a clean fermionic superfluid, showing a new feature of logarithmic divergence.