bluuebunny/crossref_metadata_2025 huggingface dataset:
AFFINE COVERS OF LIE GEOMETRIES AND THE AMALGAMATION PROPERTY
Authors: CHOWDHURY AMBAR , HART BRADD , SOKOLOVIĆ ŽELJKO
Published: October 2002

Certain classes of smoothly approximable structures — the class of affine covers of Lie geometries — are shown to have the amalgamation property. In particular, this shows that any affine cover of a Lie geometry has the small index property.

2000 Mathematical Subject Classification: 03C45.
QCD AT HIGH ENERGY
Authors: NASON PAOLO
Published: October 2002

I review few recent QCD results in e+ e-, ep and [Formula: see text] collisions. Furthermore, I discuss recent studies in power suppressed effects, ongoing progress in next-to-next-to-leading QCD calculations, and some recent puzzling results in b production.
SMALL-X QCD EFFECTS IN PARTICLE COLLISIONS AT HIGH ENERGIES
Authors: CARLI TANCREDI
Published: October 2002

Recent theoretical developments to calculate cross sections of hadronic objects in the high energy limit are summarised and experimental attempts to establish the need for new QCD effects connected with a resummation of small hadron momentum fractions x are reviewed. The relation between small-x parton dynamics and the phenomenon of diffraction is briefly out-lined. In addition, a search for a novel, non-perturbative QCD effect, the production of QCD instanton induced events, is presented.
LIGHT HADRON SPECTROSCOPY
Authors: CLOSE FRANK E.
Published: October 2002

Rapporteur talk at the Lepton-Photon Conference, Rome, July 2001: reviewing the evidence and strategies for understanding scalar mesons, glueballs and hybrids, the gluonic Pomeron and the interplay of heavy flavours and light hadron dynamics. Dedicated to the memory of Nathan Isgur, long-time collaborator and friend, whose original ideas in hadron spectroscopy formed the basis for much of the talk.
DECLINE AND FALL OF THE STANDARD MODEL?
Authors: ELLIS JOHN
Published: October 2002

Motivations for physics beyond the Standard Model are reviewed, with particular emphasis on supersymmetry at the TeV scale. Constraints on the minimal supersymmetric extension of the Standard Model with universal soft supersymmetry-breaking terms (CMSSM) are discussed. These are also combined with the supersymmetric interpretation of the anomalous magnetic moment of the muon. The prospects for observing supersymmetry at accelerators are reviewed using benchmark scenarios to focus the discussion. Prospects for other experiments including the detection of cold dark matter, μ → e γ and related processes, as well as proton decay are also discussed.
THE HIGGS PUZZLE: EXPERIMENT AND THEORY
Authors: ZWIRNER FABIO
Published: October 2002

The present experimental and theoretical knowledge of the physics of electroweak symmetry breaking is reviewed. Data still favor a light Higgs boson, of a kind that can be comfortably accommodated in the Standard Model or in its Minimal Supersymmetric extension, but exhibit a non-trivial structure that leaves some open questions. The available experimental information may still be reconciled with the absence of a light Higgs boson, but the price to pay looks excessive. Recent theoretical ideas, linking the weak scale with the size of possible extra spatial dimensions, are briefly mentioned. It is stressed once more that experiments at high-energy colliders, such as the Tevatron and the LHC, are the crucial tool for eventually solving the Higgs puzzle.
Detecting gravitational waves with ground and space interferometers – with special attention to the space project ASTROD
Authors: RÜEDIGER ALBRECHT
Published: October 2002

The existence of gravitational waves is the most prominent of Einstein's predictions that has not yet been directly verified. The space projects LISA and (partially) ASTROD share their goal and principle of operation with the ground-based interferometers currently under construction: the detection and measurement of gravitational waves by laser interferometry. Ground and space detection differ in their frequency ranges, and thus the detectable sources. Towards low frequencies, ground-based detection is limited by seismic noise, and yet more fundamentally by 'gravity gradient noise', thus covering the range from a few Hz to a few kHz. On five sites worldwide, detectors of armlengths from 0.3 to 4 km are nearing completion. they will progressively be put in operation in the years 2002 and 2003. Future enhanced versions are being planned, with scientific data not expected until 2008, i.e. near the launch of the space project LISA. It is only in space that detection of signals below, say, 1 Hz is possible, opening a wide window to a different class of interesting sources of gravitational waves. The project LISA consists of three spacecraft in heliocentric orbits, forming a triangle of 5 million km sides. A technology demonstrator, designed to test vital LISA technologies, is to be launched, aboard a SMART-2 mission, in 2006. The proposed mission ASTROD will, among other goals, also aim at detecting gravitational waves, at even lower frequencies than LISA. Its later start will allow it to benefit from the expertise gained with LISA.
Dynamical simulation of the motion of Leonid Meteoric Stream
Authors: Li Guangyu , Zhao Haibin
Published: October 2002

The Leonid meteoric shower has been the most famous meteoric shower. The main characteristics of the stream are well known, being very spectacular displays in recent years. In this paper, the authors aim at searching the dynamic origin of the second peak of Leonids 1998. Firstly a dynamic model of the solar system is constructed, considering the perturbations of the nine major planets and the Moon, Post-Newtonian effects and the figure effect of the Earth. For the motions of cornet and meteoroid, the non-gravitational effect and radiation pressure effect are taken into account separately. Secondly, the orbit of Comet Tempel-Tuttle is determined by using the observation data of this apparition. Finally, assuming an isotropic ejection model of comet, the authors simulate the motion of the meteoric stream and discover that the particles aged 2-revolutions erupted with velocity 50m/s can befall Earth at 20h37m UT of Nov. 17, 1998, which form the main part of the second peak of Leonids 1998.
GRAVITATIONAL LENS AMPLIFICATION OF GRAVITATIONAL RADIATION
Authors: ZAKHAROV ALEXANDER F. , BARYSHEV YURI V.
Published: October 2002

In a recent paper by Wang, Turner and Stebbins (1996) an influence of gravitational lensing on increasing an estimated rate of gravitational radiation sources was considered. We show that the authors used the geometrical optics approximation model for gravitational lensing and thus they gave overestimated rate of possible events for possible sources of gravitational radiation for the advanced LIGO detector. We show also that if we would use a more correct model of gravitational lensing, one could conclude that more strong influence on increasing rate of estimated events of gravitational radiation for advanced LIGO detector could give gravitational lenses of galactic masses but not gravitational lenses of stellar masses as Wang et al. concluced. Moreover, binary gravitational lenses could give essential distortion of gravitational wave form template, especially gravitational wave template of periodic sources and the effect could be significant for templates of quasi-periodic sources which could be detected by a future gravitational wave space detector like LISA.
KINEMATICAL TEST THEORIES FOR SPECIAL RELATIVITY: A COMPARISON
Authors: LÄMMERZAHL CLAUS , BRAXMAIER CLAUS , DITTUS HANSJÖRG , MÜLLER HOLGER , PETERS ACHIM , SCHILLER STEPHAN
Published: October 2002

A comparison of certain kinematical test theories for Special Relativity including the Robertson and Mansouri–Sext test theories is presented and the accuracy of the experimental results testing Special Relativity are expressed in terms of the parameters appearing in these test theories. The theoretical results are applied to the most precise experimental results obtained recently for the isotropy of light propagation and the constancy of the speed of light.
SEARCH FOR THE SPIN-SPIN INTERACTION BETWEEN ROTATING EXTENDED BODIES
Authors: ZHOU Z. B. , LUO J. , WU Z. G. , YAN Q. , SHAO C. G. , ZHANG Y. Z. , NIE Y. X.
Published: October 2002

The differential acceleration between a rotating mechanical gyroscope and a non-rotating one is directly measured by using a double free-fall interferometer, and preliminary 20-cm experimental results show that no apparent differential acceleration has been observed at the relative level of 2 × 10-6. This means that the equivalence principle is still valid for rotating extended bodies, i.e., the spin-gravitation interaction between the extended bodies has not been observed at this level. A careful error analysis is presented, and the according experimental improvement is achieved. The current background limit for 10 m-free-fall comes to about 2.6 × 10-7.
Adverse Intrauterine Conditions Diminish the Fetal Defense Against Acute Hypoxia by Increasing Nitric Oxide Activity
Authors: Gardner David S. , Fowden Abigail L. , Giussani Dino A.
Published: October 2002

Background—

The incidence of perinatal morbidity arising from birth hypoxia or asphyxia has not changed significantly in recent years despite marked improvements in labor management. Perinatal mortality in these circumstances may therefore reflect antenatal compromise and subsequent alteration of the fetal capacity to respond to episodes of hypoxia that may occur during labor. Hence, we have investigated the effects of fetal pre-exposure to a period of adverse intrauterine conditions on the mechanisms mediating the fetal defense response to a subsequent episode of acute hypoxia in sheep.

Methods and Results—

Sixteen fetal sheep were chronically instrumented at 118±2 days for recording of blood pressure, heart rate, and femoral and umbilical blood flows. In 8 of these fetuses, umbilical blood flow was reduced by 30% for 3 days (between days 125 and 128). The remaining 8 fetuses acted as sham-operated controls. Between 2 and 7 days after umbilical cord/sham compression, all fetuses were exposed to 2 episodes of acute hypoxemia on separate days during infusion with either saline or treatment with a combination of
N
G
-nitro-
l
-arginine methyl ester and sodium nitroprusside. We show that previous fetal exposure to a period of adverse intrauterine conditions, such as that induced by compression of the umbilical cord, elevates nitric oxide activity and results in a markedly diminished cardiovascular defense response to subsequent acute hypoxia.

Conclusions—

The data imply that pre-exposure to adverse antenatal conditions may render the fetus more susceptible to the acute hypoxia or asphyxia that can accompany relatively uncomplicated labor and delivery.
Modulation of QT Interval During Autonomic Nervous System Blockade in Humans
Authors: Diedrich André , Jordan Jens , Shannon John R. , Robertson David , Biaggioni Italo
Published: October 2002

Background—

It is thought that the autonomic nervous system modulates QT interval, but traditional autonomic blockade combining propranolol and atropine has produced conflicting results. We used the alternative approach of interrupting neurotransmission at the level of autonomic ganglia to determine its effect on the QT interval.

Methods and Results—

We infused trimethaphan at increasing doses (0.5 to 10 mg/min IV) while monitoring heart rate, heart rate variability spectra, QT interval, and blood pressure in 10 normal volunteers, 9 patients with multiple system atrophy (MSA), and 8 patients with pure autonomic failure (PAF). The QT interval was corrected for heart rate using Bazett’s formula (QTc). Patients with PAF had very low heart rate variability and a prolonged QTc at baseline (465±8 ms) compared with patients with MSA (448±6 ms) and normal subjects (432±6 ms). In normal subjects, trimethaphan dose-dependently prolonged QTc (to 469±7 ms), decreased RR interval (995±45 to 670±35 ms), and abolished heart rate variability. In MSA patients, trimethaphan also prolonged QTc (to 463±7 ms) and reduced heart rate variability but did not significantly change RR interval (from 813±38 to 801±39).

Conclusions—

Autonomic blockade prolongs QT interval in normal subjects to a similar duration as in PAF patients. Furthermore, blocking residual autonomic tone in PAF patients is associated with a further increase in QT interval length. Patients with MSA have greater residual sympathetic tone and greater prolongation of the QT interval during ganglionic blockade than PAF patients.
Iron Therapy, Advanced Oxidation Protein Products, and Carotid Artery Intima-Media Thickness in End-Stage Renal Disease
Authors: Drüeke Tilman , Witko-Sarsat Véronique , Massy Ziad , Descamps-Latscha Béatrice , Guerin Alain P. , Marchais Sylvain J. , Gausson Valérie , London Gérard M.
Published: October 2002

Background—

Increased common carotid artery intima-media thickness (CCA-IMT) is a marker of early atherosclerosis. Low-grade inflammation is associated with the pathogenesis of atherosclerosis. Low-grade inflammation and increased CCA-IMT are observed in end-stage renal disease (ESRD). Oxidative stress is involved in uremia-related inflammation. Advanced oxidation protein products (AOPP) are markers of oxidant-mediated protein damage in ESRD. Intravenous iron given to patients on hemodialysis (HD) might induce oxidative stress. We investigated the relationships between AOPP, iron therapy, and CCA-IMT in stable HD patients.

Methods and Results—

Plasma AOPP and blood chemistry, including iron status, were analyzed in a cohort of 79 ESRD patients on HD. Measurements of CCA-IMT and CCA diameter, as assessed by B-mode ultrasonography, were obtained in 60 patients. AOPP levels were elevated in ESRD patients, and in univariate (
r
=0.42,
P
<0.0001) and multivariate analyses (
r
=0.38,
P
<0.001), they correlated with serum ferritin and with the intravenous iron dose received during the 12 months preceding the study (ferritin,
P
<0001; AOPP,
P
<0.01). Univariate and multivariate analyses identified the AOPP concentration as being significantly associated with CCA-IMT (
P
=0.0197) and CCA wall-to-lumen ratio (
r
=0.560,
P
<0.0001). Independently of AOPP concentration, cumulative iron dose was positively related to CCA-IMT (
P
=0.015) in patients <60 years.

Conclusion—

In ESRD patients, CCA-IMT and CCA wall-to-lumen ratio were associated with plasma AOPP, serum ferritin, and the annual intravenous iron dose administered. These findings support the concept of a role of oxidative stress in the early atherosclerosis of ESRD patients, which may be increased by the usually recommended doses of intravenous iron.
Coronary Plaque Classification With Intravascular Ultrasound Radiofrequency Data Analysis
Authors: Nair Anuja , Kuban Barry D. , Tuzcu E. Murat , Schoenhagen Paul , Nissen Steven E. , Vince D. Geoffrey
Published: October 2002

Background—

Atherosclerotic plaque stability is related to histological composition. However, current diagnostic tools do not allow adequate in vivo identification and characterization of plaques. Spectral analysis of backscattered intravascular ultrasound (IVUS) data has potential for real-time in vivo plaque classification.

Methods and Results—

Eighty-eight plaques from 51 left anterior descending coronary arteries were imaged ex vivo at physiological pressure with the use of 30-MHz IVUS transducers. After IVUS imaging, the arteries were pressure-fixed and corresponding histology was collected in matched images. Regions of interest, selected from histology, were 101 fibrous, 56 fibrolipidic, 50 calcified, and 70 calcified-necrotic regions. Classification schemes for model building were computed for autoregressive and classic Fourier spectra by using 75% of the data. The remaining data were used for validation. Autoregressive classification schemes performed better than those from classic Fourier spectra with accuracies of 90.4% for fibrous, 92.8% for fibrolipidic, 90.9% for calcified, and 89.5% for calcified-necrotic regions in the training data set and 79.7%, 81.2%, 92.8%, and 85.5% in the test data, respectively. Tissue maps were reconstructed with the use of accurate predictions of plaque composition from the autoregressive classification scheme.

Conclusions—

Coronary plaque composition can be predicted through the use of IVUS radiofrequency data analysis. Autoregressive classification schemes performed better than classic Fourier methods. These techniques allow real-time analysis of IVUS data, enabling in vivo plaque characterization.
The African Rhigonematoidea (Nematoda: Rhigonematida). 1. Trachyglossus quintus gen. n., sp. n. (Xustrostomatidae fam. n.) with redescription of Rhigonema multipapillatum (Skrjabin, 1916) and designation of a neotype
Authors: Hunt David
Published: October 2002

Trachyglossus quintus gen. n., sp. n. is described from Charactopygus frequens from Zaire. The new genus is characterised by having a dorsoventrally elongate oral aperture with the dorsal jawplate developed into a tongue-like rasp extending over halfway down the corpus lumen; a hypertrophied corpus and isthmus; well developed, lobate caudal alae in the male; hypertrophied, lobiform, vulval flap and by the form of the spicules and disposition of the copulatory papillae. It is closest to Xustrostoma, a genus with which it shares the development of a tongue-like rasp, but differs principally in the hypertrophy of the pharyngeal components: in Trachyglossus gen. n. it is the corpus and isthmus which are enlarged whereas in Xustrostoma it is the basal bulb. Trachyglossus gen. n. also differs in having strongly developed, lobate, caudal alae in the male (vs absent) and in possessing a lobiform anterior vulval lip. It differs from Obainia in having the dorsal jaw plate modified to form a tongue-like rasp, corpus and isthmus region of pharynx hypertrophied (vs basal bulb in African species of Obainia), hypertrophied vulval flap, form of spicules, distribution of copulatory papillae and presence of caudal alae in the male. From Zalophora it differs in the form of the pharynx, development of a tongue-like dorsal rasp instead of numerous teeth on the dorsal jawplate, presence of a hypertrophied vulval lobe and in being amphimictic instead of parthenogenetic. Xustrostomatidae fam. n. is proposed for all those genera (formerly included in the Rhigonematidae) with the cephalic capsule laterally compressed to form a dorsoventrally orientated oral aperture. Rhigonema multipapillatum (Skrjabin, 1916), previously known only from the original description, is redescribed and established as a valid species on the basis of material from Uganda. A neotype is proposed. The species is characterised by medium body size; posterior margin of cephalic collar fused to body; presence of fine microtrichs in the cervical region; cuticularised mouth plates clothed in minute spine-like structures; Type 1 female genital tract; conoid spicate tail shape in both sexes; form of the long, slender spicules and disposition of the 31 copulatory papillae, three postcloacal pairs of which being subdorsal or sublateral in position.
Free-living nematodes from nature reserves in Costa Rica. 3. Araeolaimida
Authors: Zullini Aldo , Loof Pieter , Bongers Tom
Published: October 2002

Seven species of Araeolaimida were found in soil, moss and freshwater habitats of tropical forests in Costa Rica. Three are described as new. Anonchus pulcher n. sp. is characterised by slender body, lip region demarcated by a depression, presence of ca 45- 60 sublateral glands on each side of the body and monoprodelphic female genital apparatus. Paraplectonema americanum n. sp. lacks somatic setae, the stoma is 3.0-3.4 lip region diameter long, the female rectum measures 26 μm, the male tail 137-153 μm, presence of ten to 11 male supplements, spicula 28-30 μm long, gubernaculum of complicated shape with a caudal apophysis. Chronogaster costaricae n. sp. is characterised by absence of longitudinal incisures, rows of spines, crystalloids and vacuolated glandular bodies, terminus with open mucro with one or two basal spines. The species redescribed, either briefly for well known, or more extensively for less well known, species are: Plectus patagonicus de Man, 1904; P.indicus Khera, 1972; Chronogaster serrulata Loof, 1973 and C. cameroonensis Heyns & Coomans, 1984.
Morphology and systematics of the genus Anonchus Cobb, 1913 (Nematoda: Leptolaimina) and reappraisal of the family Aphanolaimidae Chitwood, 1936 n. rank
Authors: Zullini Aldo , Holovachov Oleksandr , Loof Pieter , Bongers Tom
Published: October 2002

The genus Anonchus is revised. The genera Assia and Haconnus are considered to be synonymous with Anonchus on the basis of the morphological analysis. Additional descriptions of six species, viz. A. maculatus , A. mirabilis , A. millelacunatus , A. palaeotropicus , A. coomansi and A. pulcher are provided on the basis of type material or recently collected populations. The lectotype of A. monohystera is designated and described and the synonymy of this species with A. maculatus is confirmed. Two new species are described; A. winiszewskae sp. n. from Paraguay and A. venezolanus sp. n. from Venezuela. Several aspects of the morphology are described and the variability and diagnostic significance of the main morphological characters discussed. A study of intrageneric and suprageneric taxonomy of the genus Anonchus is presented. The subfamily Aphanolaiminae is reinstated for the genera Aphanolaimus, Aphanonchus and Paraphanolaimus and raised to family rank. The family Aphanolaimidae includes two subfamilies: Aphanolaiminae and Anonchinae. An emended diagnosis and a revised classification of Anonchus are proposed and a key to the species of the genus is provided.
Synthesis and properties of anionic aqueous polyurethane dispersions
Authors: Lu M. G. , Lee J. Y. , Shim M. J. , Kim S. W.
Published: October 2002

A series of aqueous polyurethane dispersions containing pendant carboxylate anion as the hydrophilic were synthesized, and the particle size and the mechanical properties of the dispersions were measured. The effects of the molar ratio of NCO/OH groups or the other functional groups on the chemical structure and the properties were discussed. The particle size mainly depended on the molar ration of the functional groups. The NH groups in urethane and urea linkage formed hydrogen bonding with the carbonyl group (CO) of other urethane group in the hard segments or ether group (COC) in the soft segments. Fourier transform infrared (FTIR) analysis showed that the higher molar ratio of NCO/OH concentrated the NH group, leading to the hydrogen bonding, which resulted in the increasing mechanical strength of the polyurethane. The tensile testing and dynamic mechanical analysis measurement revealed that the pendant carboxylate anion made the modulus and the stiffness of the polyurethane increase. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3461–3465, 2002
Synthesis and properties of novel fluoroalkyl end‐capped oligomers containing silsesquioxane segments
Authors: Sawada Hideo , Yoshioka Hiroaki , Ohashi Ryusei , Kawase Tokuzo
Published: October 2002

Fluoroalkyl end‐capped homo‐ and co‐ oligomers containing silsesquioxane segments were prepared by the reactions of fluoroalkanoyl peroxides with the corresponding methacrylate monomer‐bearing silsesquioxane unit (Si‐MMA) and comonomers such as N,N‐dimethylacrylamide (DMAA) and acrylic acid (ACA). These new fluorinated Si‐MMA oligomers were easily soluble in various organic solvents and were able to reduce the surface tension of m‐xylene effectively. The modified poly(methyl methacrylate) [PMMA] and glass surface treated with fluorinated Si‐MMA homo‐oligomers exhibited a strong oleophobicity, although these fluorinated oligomers possess high oleophilic silsesquioxane segments. In contrast, the modified PMMA surface treated with fluorinated Si‐MMA–DMAA cooligomers exhibited a good hydrophilicity with a strong oleophobicity. In a series of fluorinated Si‐MMA oligomers, fluorinated Si‐MMA homo‐oligomers had a relatively high thermal stability. Therefore, these fluoroalkyl end‐capped Si‐MMA oligomers are suggested to have high potential for new functional materials through their unique properties such as a high solubility and surface active properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3486–3493, 2002
Heterocyclic‐based epoxy‐terminated structural adhesive. II. Curing, adhesive strength, and thermal stability
Authors: Bhuniya Sankar , Maiti Sukumar
Published: October 2002

We studied the curing behavior of heterocyclic‐based epoxy‐terminated resins using diaminodiphenyl ether, diaminodiphenyl sulfone, benzophenone tetracarboxylicdianhydride, and the commercial hardener of Ciba‐Geigy's two‐pack Araldite as curing agents. The adhesive strength of the adhesives was measured by various ASTM methods such as lap‐shear, peel, and cohesive tests on metal–metal, wood–wood, and wood–metal interfaces. All of these results were compared with those of an epoxy resin prepared from bisphenol‐A and epichlorohydrin resin with an epoxy equivalent value of 0.519. The thermal stability of both the virgin resin and its cured form was also studied by thermogravimetric analysis. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3520–3526, 2002
Kinetic model of block photopolymerization of glycidyl methacrylate to high conversion
Authors: Medvedevskikh Yu. , Bratus A. , Hafiychuk G. , Zaichenko A. , Kytsya A. , Turovski A. , Zaikov G.
Published: October 2002

The kinetics of glycidyl methacrylate block polymerization to high conversion was experimentally investigated with variations of the photoinitiator concentration, temperature, and power of UV illumination. The kinetic curves of this polymerization process contain three characterized sections of coordinates of “conversion–time,” namely: The first one is practically linear to a conversion of ≈0.5, the second represents, by itself, the autoacceleration process, and the third presents the autodecelation process. An additional peculiarity of such a polymerization process is poor reproduction of the kinetic measurements. This reproduction does not correspond to instrumental error. Derivation of a kinetic model for block linear polymerization was done. This model is, quantitatively, in good agreement with all the data of the experimental material. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3556–3569, 2002
Synthesis and properties of radiation‐induced acrylamide–acrylic acid hydrogels
Authors: Şolpan Dilek , Duran Sibel , Güven Olgun
Published: October 2002

Acrylamide (AAm)/acrylic acid (AAc) hydrogels in the cylindirical form were prepared by γ‐irradiating binary systems of AAm/AAc with 2.6–20.0 kGy γ‐rays. The effect of the dose and relative amounts of AAc and pH on the swelling properties, diffusion behavior of water, diffusion coefficients, and network properties of hydrogel systems was investigated. The swelling capacities of AAm/AAc hydrogels were in the range of 1000–3000%, while poly(acrylamide) (PAAm) hydrogels swelled in the range of 450–700%. Water diffusion into hydrogels was found to be non‐Fickian‐type diffusion. Diffusion coefficients of AAm/AAc hydrogels were found between 0.79 × 10−5 and 2.78 × 10−5 cm2 min−1. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3570–3580, 2002
Structure modification and crosslinking of methacrylated polylactide oligomers
Authors: Helminen Antti O. , Korhonen Harri , Seppälä Jukka V.
Published: October 2002

The effect of molecular architecture on the properties of crosslinked polylactides was studied. D,L‐Lactide‐based telechelic oligomers with different numbers of arms were functionalized with methacrylic anhydride. Functionalized oligomers were crosslinked with thermal initiation at 90°C, and the mechanical and thermal properties, as well as the gel content, were evaluated. The crosslinking density increased with the number of arms in the oligomers, and the compressive yield strength was built up at the same time. The best mechanical properties (compressive yield strength = 120 MPa, modulus = 2800 MPa, and strain = 5.0%) were obtained with cured polymers prepared with a 100 : 8 ratio of lactide to pentaerythritol. When dimethacrylated butanediol was used as a reactive monomer in curing, polymers with high crosslinking density and mechanical strength were obtained at 37, 60, and 90°C. The use of the reactive monomer also enabled high conversions with photoinitiated crosslinking. Finally, hydrolytic degradation and strength retention were demonstrated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3616–3624, 2002
An improved molecularly imprinted polymer film for recognition of amino acids
Authors: Sneshkoff N. , Crabb K. , BelBruno J. J.
Published: October 2002

A highly selective imprinted film was produced from a formic acid solution of nylon. Amino acids were used as template molecules and spin cast films typically of the order of 1 μm, but as thin as 500 nm, were routinely prepared. The films were shown to be specific to the identity and chirality of the template amino acid, and were shown to be effective after as many as five cycles of template extraction and reintroduction. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3611–3615, 2002
Low‐temperature photoinitiation solution polymerization behavior of N‐vinylcarbazole in tetrahydrofuran
Authors: Lyoo Won Seok , Ghim Han Do , Kim Hee‐Sam , Kim Joon Ho , Kim Sam Soo , Yoon Won Sik , Lee Jinwon , Lee Sang‐Seob
Published: October 2002

N‐Vinylcarbazole (VCZ) was solution‐polymerized in tetrahydrofuran (THF) at −20, 0, and 20°C using the photoinitiation method; the effects of the amount of solvent, polymerization temperature, and photoinitiator concentration were investigated. On the whole, the experimental results corresponded to predicted ones. Low polymerization temperature using photoinitiation proved to be successful in obtaining poly(N‐vinylcarbazole) (PVCZ) of a high molecular weight with a smaller temperature rise during polymerization; nevertheless of free radical polymerization by 2,2′‐azobis(2,4‐dimethylvaleronitrile) (ADMVN). The photo‐solution polymerization rate of VCZ in THF was proportional to the 0.47 power of ADMVN concentration. The molecular weight was higher and the molecular weight distribution was narrower with PVCZ polymerized at lower temperatures. For PVCZ prepared in THF at −20°C using a photoinitiator concentration of 0.00005 mol/mol of VCZ, a weight‐average molecular weight of 510,000 was obtained, with a polydispersity index of 1.73, and a degree of lightness converged to about 99%. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3667–3672, 2002
Rheological properties of a new rubbery nanocomposite: Polyepichlorohydrin/organoclay nanocomposites
Authors: Lim Sang K. , Kim Ji W. , Chin I‐J. , Choi Hyoung J.
Published: October 2002

Nanocomposites of organophilic montmorillonite clay (OMMT) and polyepichlorohydrin (PECH) were intercalated by a solvent‐casting method using dichloromethane as a solvent. The intercalation of PECH segments in the interlayers of the clay was confirmed by X‐ray diffraction, and the intercalation spacing was calculated. The increase in the onset temperature of the thermal degradation indicated the enhancement of thermal stability of PECH due to intercalation. Rheological properties of the PECH/OMMT nanocomposites were investigated using a rotational rheometer in a steady shear mode. The steady shear viscosity increased with the clay loading, and the shear thinning viscosity data were fitted well with the Carreau model. From the normalized shear viscosity analysis, a critical shear rate that is a crossover from a Newtonian plateau to a shear thinning region was found to approximately equal the inverse of the characteristic time of the nanocomposites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3735–3739, 2002
Ortho‐aminobenzoic acid‐labeled bradykinins in interaction with lipid vesicles: Fluorescence study
Authors: Turchiello R. F. , Lamy‐Freund M. T. , Hirata I. Y. , Juliano L. , Ito A. S.
Published: October 2002

The peptide hormone bradykinin (BK) (Arg1‐Pro2‐Pro3‐Gly4‐Phe5‐Ser6‐Pro7‐Phe8‐Arg9) and its shorter homolog BK1–5 (Arg1‐Pro2‐Pro3‐Gly4‐Phe5) were labeled with the extrinsic fluorescent probe ortho‐aminobenzoic acid (Abz) bound to the N‐terminal and amidated in the C‐terminal carboxyl group (Abz‐BK‐NH2 and Abz‐BK1–5‐NH2). The fragment des‐Arg9‐BK was synthesized with the Abz fluorescent probe attached to the 3‐amino group of 2,3‐amino propionic acid (DAP), which positioned the Abz group at the C‐terminal side of BK sequence, constituting the peptide des‐Arg9‐BK‐DAP(Abz)‐NH2. The spectral characteristics of the probe were similar in the three peptides, and their fluorescent properties were monitored to study the interaction of the peptides with anionic vesicles of dimyristoylphosphatidylglycerol (DMPG). Time‐resolved fluorescence experiments showed that the fluorescence decay of the peptides was best described by double‐exponential kinetics, with mean lifetimes values around 8.0 ns in buffer pH 7.4 that increased about 10% in the presence of DMPG vesicles. About a 10‐fold increase, compared with the values in aqueous solution, was observed in the steady‐state anisotropy in the presence of vesicles. A similar increase was also observed for the rotational correlation times obtained from time‐resolved anisotropy decay profiles, and related to the overall tumbling of the peptides. Equilibrium binding constants for the peptide–lipid interaction were examined monitoring anisotropy values in titration experiments and the electrostatic effects were evaluated through Gouy–Chapman potential calculations. Without corrections for electrostatic effects, the labeled fragment Abz‐BK1–5‐NH2 presented the major affinity for DMPG vesicles. Corrections for the changes in peptide concentration due to electrostatic interactions suggested higher affinity of the BK fragments to the hydrophobic phase of the bilayer. © 2002 Wiley Periodicals, Inc. Biopolymers 65: 336–346, 2002
Choline acetyltransferase immunoreactivity in the developing brain of Xenopus laevis
Authors: López Jesús M. , Smeets Wilhelmus J.A.J. , González Agustín
Published: October 2002

The spatiotemporal sequence of the appearance of cholinergic structures in the brain of Xenopus laevis during development was studied by means of choline acetyltransferase (ChAT) immunohistochemistry. The first ChAT labeling in the central nervous system of Xenopus was obtained at late embryonic stages in the spinal motoneurons, the cranial nerve motor nuclei of the brainstem, and in amacrine cells of the retina. During premetamorphosis, these cholinergic structures maturated significantly and new ChAT‐immunoreactive cells were observed in several other nuclei such as the solitary tract nucleus, isthmic nucleus, laterodorsal and pedunculopontine tegmental nuclei, epiphysis, dorsal habenular nucleus, medial amygdala, bed nucleus of the stria terminalis, and dorsal pallidum. Further maturation continued through prometamorphosis and the climax of the metamorphosis together with the appearance of new cell groups in the efferent octaval nucleus, ventral hypothalamic nucleus, anterior preoptic area, suprachiasmatic nucleus, and medial septum. Transient expression of ChAT was only seen in the large Mauthner cells that showed moderate ChAT labeling during pre‐ and prometamorphosis but became immunonegative at the end of the metamorphosis. The gradual appearance, in general from caudal to rostral brain levels, of ChAT immunoreactivity in Xenopus, was correlated with other developmental events to get insight into the possible roles of acetylcholine during ontogeny. Comparison with the developmental pattern of cholinergic systems in other vertebrates shows that Xenopus possesses abundant features in common with amniotes, suggesting a conservative developmental plan for tetrapods. J. Comp. Neurol. 453:418–434, 2002. © 2002 Wiley‐Liss, Inc.
Formation of parabolic dunes from barchan and transverse dunes along Israel's Mediterranean coast
Authors: Tsoar Haim , Blumberg DAN G.
Published: October 2002

The Mediterranean coastal dunes of Israel underwent a land‐use change during the second half of the 20th century. Due to intense agricultural and pastoral activity, the coastal dunes were stripped of natural vegetation until the end of the first half of the 20th century. The barchan and transverse dunes were shaped by strong southwesterly winter winds. A decrease in human activity during the second half of the 20th century brought about a renewal of natural vegetation on the dune crest—the only area with neither erosion nor deposition. The establishment of vegetation on the crest changes the dynamics of these barchan and transverse dunes, so that not all of the sand eroded from the windward side is carried to the lee slip‐face; some is trapped by plants. Consequently, there is a change in the shape of the windward slope from convex to concave, and the dune gradually becomes parabolic. In this study we trace the morphodynamics of the dunes by analysing 12 sets of aerial photographs, which were taken from 1944 to 1995. The average rate of advance of 15 dunes has decreased from 3·4 m a−1to 1·9 m a−1, while the vegetation cover has increased from 4·3 to 17 per cent during this period. Copyright © 2002 John Wiley & Sons, Ltd.
Long‐term landform evolution: evidence from talus studies
Authors: van Steijn Henk
Published: October 2002

Current concepts of long‐term landform change like equilibrium, characteristic forms or the role of climate were developed with the denudational history of landscapes in mind. In this paper some long‐term aspects of talus development are discussed as an example of the potential contribution from dominantly depositional environments to the more theoretical concepts of geomorphology. Evolutions during periods of 102 to 103 years as well as during longer periods (in the order of 104 to 105 years) are mentioned. Interpretations of geomorphological evolution for the latter time scale and within a regional context may be obtained from the information contained within the shorter time slices studied in detail on individual taluses. Periods for which the evolution of part of a talus is known in detail, in terms of process types and sequences in relation to climate and other environmental factors, are indicated here as time slices. It is suggested that the combination of such time slices for a given region may result in a more or less complete picture of geomorphological and environmental evolution for relatively long periods. The image obtained is additional to information from other reconstructions of environmental conditions. Two examples of talus research are discussed to explain the intentions of the paper.

Concluding statements draw attention to the potentially strong relationships between properties of talus deposits and environmental conditions. This is especially important for information that cannot be obtained from other sources like pollen analysis, for instance about precipitation characteristics. At a more general level of geomorphology, a possible modification of ideas is proposed about the influence of climate on the functioning of certain geomorphological systems. Further consequences of the results are the need to re‐think concepts like equilibrium or characteristic form. Copyright © 2002 John Wiley & Sons, Ltd.
A review of two strongly contrasting geomorphological systems within the context of scale
Authors: Cammeraat L. H.
Published: October 2002

Scale issues are often addressed in contemporary geo‐ecological studies and form one of the major challenges in the fields of physical geography, hydrology and ecology. In this paper the application of hierarchy theory and response units is proposed as an approach towards scale‐transcending environmental studies on degradation and geomorphological development.

Goals of the research were to establish which processes are important at what spatio‐temporal scale, how hydro‐geomorphological response is influenced by biological processes and whether hierarchy theory and the response unit approach can be used as an up‐scaling methodology.

Results from two climatologically and geomorphological different regions are discussed, one dominated by water shortage (SE Spain) and the other by water surplus (Luxembourg). In both cases detailed process research was carried out at scales ranging from the micro‐plot to the catchment. Process research was concentrated on understanding and quantifying sediment and water transfer through the geo‐ecosystems studied.

Outcomes showed that in both cases the role of biological processes was important in the hydrological and degradation response of both areas. This was not only true for the finest scale levels but also had its impact on the emerging properties and response at the hillslope and catchment level.

Connectivity of runoff‐generating and runoff‐absorbing areas was important on all scale levels. Connectivity is dominated by both the rainfall magnitude–frequency–duration characteristics and physically and biologically controlled thresholds, which range from initial soil moisture contents, vegetation patterns or soil biological activity, to the presence of water harvesting structures.

The complex interrelationships of the processes involved showed that linear up‐scaling from fine to broad scale is impossible, as many thresholds and non‐linear processes are involved at specific scales. The identified response units are used to integrate these complex relationships in a relatively manageable way, and may provide a useful framework for up‐scaling, and for understanding catchment hydro‐geomorphological response and development. Copyright © 2002 John Wiley & Sons, Ltd.
Distributional properties of EMS and non‐EMS exchange rates before and after German reunification
Authors: Laopodis Nikiforos T.
Published: October 2002

The paper explores the stochastic behaviour of four EMS (Belgian franc, French franc, Spanish peseta and Italian lira) and non‐EMS (Canadian dollar, US dollar, Japanese yen and British pound) deutschemark exchange rates, using a GARCH‐type model along with the generalized error distribution, before and after Germany's unification in 1990. The results indicate that there was a fundamental change in the distributions of all exchange rates after Germany's reunification and so the single normal distribution assumption is not appropriate. Although the presence of GARCH remained, all rates' conditional distributions resembled the uniform, in the first period, but they approximated the double exponential in the second. Further, during and after the pound's brief and the lira's longer associations with the ERM their distributions were unchanged. Finally, two other notable results were the reduction in the degree of volatility persistence in all Deutschemark rates during the after‐unification period, and the rates' strong mean‐reverting tendencies. Copyright © 2002 John Wiley & Sons, Ltd.
An infinite series of regular edge‐ but not vertex‐transitive graphs
Authors: Lazebnik Felix , Viglione Raymond
Published: October 2002

Let n be an integer and q be a prime power. Then for any 3 ≤ n ≤ q−1, or n=2 and q odd, we construct a connected q‐regular edge‐but not vertex‐transitive graph of order 2qn+1. This graph is defined via a system of equations over the finite field of q elements. For n=2 and q=3, our graph is isomorphic to the Gray graph. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 249–258, 2002
6‐regular 4‐critical graph
Authors: Pyatkin A. V.
Published: October 2002

P. Erdős conjectured in [2] that r‐regular 4‐critical graphs exist for every r ≥ 3 and noted that no such graphs are known for r ≥ 6. This article contains the first example of a 6‐regular 4‐critical graph. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 286–291, 2002
Recursive generation of partitionable graphs
Authors: Boros E. , Gurvich V. , Hougardy S.
Published: October 2002

Results of Lovász (1972) and Padberg (1974) imply that partitionable graphs contain all the potential counterexamples to Berge's famous Strong Perfect Graph Conjecture. A recursive method of generating partitionable graphs was suggested by Chvátal, Graham, Perold, and Whitesides (1979). Results of Sebő (1996) entail that Berge's conjecture holds for all the partitionable graphs obtained by this method. Here we suggest a more general recursion. Computer experiments show that it generates all the partitionable graphs with ω=3,α ≤ 9 (and we conjecture that the same will hold for bigger α, too) and many but not all for (ω,α)=(4,4) and (4,5). Here, α and ω are respectively the clique and stability numbers of a partitionable graph, that is the numbers of vertices in its maximum cliques and stable sets. All the partitionable graphs generated by our method contain a critical ω‐clique, that is an ω‐clique which intersects only 2ω−2 other ω‐cliques. This property might imply that in our class there are no counterexamples to Berge's conjecture (cf. Sebő (1996)), however this question is still open. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 259–285, 2002
Proof of a conjecture on irredundance perfect graphs
Authors: Volkmann Lutz , Zverovich Vadim E.
Published: October 2002

Let ir(G) and γ(G) be the irredundance number and the domination number of a graph G, respectively. A graph G is called irredundance perfect if ir(H)=γ(H), for every induced subgraph H of G. In this article we present a result which immediately implies three known conjectures on irredundance perfect graphs. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 292–306, 2002
Edge‐partitions of planar graphs and their game coloring numbers
Authors: He Wenjie , Hou Xiaoling , Lih Ko‐Wei , Shao Jiating , Wang Weifan , Zhu Xuding
Published: October 2002

Let G be a planar graph and let g(G) and Δ(G) be its girth and maximum degree, respectively. We show that G has an edge‐partition into a forest and a subgraph H so that (i) Δ(H) ≤ 4 if g(G) ≥ 5; (ii) Δ(H) ≤ 2 if g(G) ≥ 7; (iii) Δ(H)≤ 1 if g(G) ≥ 11; (iv) Δ(H) ≤ 7 if G does not contain 4‐cycles (though it may contain 3‐cycles). These results are applied to find the following upper bounds for the game coloring number colg(G) of a planar graph G: (i) colg(G) ≤ 8 if g(G) ≥ 5; (ii) colg(G)≤ 6 if g(G) ≥ 7; (iii) colg(G) ≤ 5 if g(G) ≥ 11; (iv) colg(G) ≤ 11 if G does not contain 4‐cycles (though it may contain 3‐cycles). © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 307–317, 2002
Two graphs without planar covers
Authors: Archdeacon Dan
Published: October 2002

In this note we prove that two specific graphs do not have finite planar covers. The graphs are K7–C4 and K4,5–4K2. This research is related to Negami's 1‐2‐∞ Conjecture which states “A graph G has a finite planar cover if and only if it embeds in the projective plane.” In particular, Negami's Conjecture reduces to showing that 103 specific graphs do not have finite planar covers. Previous (and subsequent) work has reduced these 103 to a few specific graphs. This paper covers 2 of the remaining cases. The sole case currently remaining is to show that K2,2,2,1 has no finite planar cover. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 318–326, 2002
Effect of light and oxygen transmission characteristics of packaging materials on photo‐oxidative quality changes in semi‐hard Havarti cheeses
Authors: Mortensen Grith , Sørensen John , Stapelfeldt Henrik
Published: October 2002

Changing transmission characteristics of food packaging materials by colouring the materials may be a suitable way of reducing photo‐oxidative quality changes. This study proved that packaging in black laminates provided the best protection of Havarti cheese, followed by a white laminate. However, transparent packaging materials did not protect the product in the critical wavelength range, i.e. 400–500 nm, and changes in colour and odour were already notable after few hours of exposure to fluorescent light. Additionally, secondary oxidation products, hexanal, 1‐pentanol, and 1‐hexanol, were formed in cheese packaged in transparent or semi‐transparent packaging materials. The expected effects of oxygen transmission were difficult to evaluate, due to high residual oxygen levels in the packages. Copyright © 2002 John Wiley & Sons, Ltd.