bluuebunny/crossref_metadata_2025 huggingface dataset:
DEFECTS AND WAVES IN A MODEL OF SUPERFLUID
Authors: POMEAU Y.
Published: November 2004

Among physical systems whose physical properties depend on singularities and display some kind of pattern, superfluids play a quite interesting role, because of their quantum nature: in addition to the usual translation and rotation invariance, their invariance in a global phase change has no classical counterpart. This has rather subtle consequences that will be explored, particularly in reference to the problem of limit speed and to the phenomenology linked to the roton spectrum. Using concepts borrowed from pattern formation theory, one may understand the limit speed as the onset of a kind of Eckhaus instability leading to the formation of topo logical defects. Similarly, the emission of rotons may be viewed as resulting from an instability quite similar to a local Rayleigh-Bénard instability.
MECHANISM OF PARAMETRIC RESONANCE OF VORTICES IN EXCITABLE MEDIA
Authors: MUÑUZURI A.P. , PÉREZ-MUÑUZURI V. , GÓMEZ-GESTEIRA M. , KRINSKY V.I. , PÉREZ-VILLAR V.
Published: November 2004

An alternating electric current induces a drift of spiral waves (vortices) in the Belousov-Zhabotinsky reaction. When the electric current frequency is twice the frequency of the vortex rotation, the vortex drifts with a velocity about 1/5 of the vortex drift in a constant electric current or 1/20 of the wave front velocity. The dependence of parametric resonance on the chirality of the vortex, excitability of the medium, phase shift between electric current and vortex rotation, frequency and amplitude of the alternating electric current is analyzed and used to control the direction and velocity of the drift. A kinematical model, based on the asymmetric effect of the current on the normal and tangential velocities of the vortex tip, is formulated and recovers the most important aspects of parametric resonance.
ON THE NUMERICAL DETECTION OF CODIMENSION-3 BIFURCATIONS OF PERIODIC SOLUTIONS (WITH APPLICATION TO OPTICAL BISTABILITY)
Authors: NOLTE KLAUS-GEORG , L’HEUREUX IVAN
Published: November 2004

Based upon the combination of the pseudo-arclength continuation method and the Poincaré map defined on a variable return plane, systems of equations are constructed that trace a Takens-Bogdanov bifurcation, a cusp, an isola formation/perturbed bifurcation point and a degenerate period-doubling/secondary Hopf bifurcation of periodic solutions of autonomous ordinary differential equations. The implementation of these ideas into a collection of FORTRAN codes and its application to a five-dimensional system describing an optical bistable system lead to the detection of interesting codimension-3 bifurcations away from the stationary behavior. A winged cusp, a swallow tail, a degenerate hysteresis point, an isola formation point for a codimension-1 loop and two kinds of degenerate Takens-Bogdanov bifurcations of periodic solutions are presented. Finally, based upon the computation of the stability coefficient “a”, attractive tori are found in a systematic way and briefly discussed.
SELF-SYNCHRONIZATION OF MANY COUPLED OSCILLATORS
Authors: VIEIRA M. DE SOUSA , LICHTENBERG A.J. , LIEBERMAN M.A.
Published: November 2004

We investigate the synchronization to a common frequency and phase in systems of many coupled digital phase-locked loops. We study cases for which the internal frequencies are identical for all loops and for which they are different. In both cases, we observe that synchronization to a common frequency is possible in a range of the parameter space. We find an analytical expression for the synchronization frequency when the communication between loops is in two directions. Synchronization in phase occurs only when the internal frequencies of the loops are identical. We study the transient convergence to the locked state in the ring, double ring, and global coupling configurations. We also discuss the influence of a multiperiodic or chaotic loop on the dynamics of the system. Our results may have applications to the problem of network synchronization.
DETERMINISTIC FRACTAL GEOMETRY AND PROBABILITY
Authors: PUENTE CARLOS E.
Published: November 2004

A possible connection between deterministic fractal geometry and the most important probabilistic models (Gaussian distribution and Brownian motion) is exhibited.
CONTROLLING CHAOS THROUGH ITERATION SEQUENCES AND INTERPOLATION TECHNIQUES
Authors: STÄMPFLE M.
Published: November 2004

Chaotic systems can be controlled by parametric variation methods. This paper proposes a new algorithm which exploits given sequences of system states, and approximates the system dynamics by interpolation techniques. As a special feature, the method allows arbitrary goal dynamics, and thus covers a wide range of applications. The algorithm controls periodic so lutions and shortens transient phases between the stabilization of different orbits. Practical examples include the Hénon map and the Lorenz equation.
RADIATED ACOUSTIC PRESSURE FROM A MOVING, NONUNIFORMLY VIBRATING CYLINDER WITH TWO SPHERICAL ENDCAPS
Authors: WANG ZHAOXI , WU SEAN F.
Published: November 2004

This paper presents numerical results of radiated acoustic pressures from a moving, nonuniformly vibrating cylinder with two spherical endcaps, based on an extended Kirchhoff integral formulation. Specifically, we consider cases in which the normal component of the surface velocity is nonzero on a portion of the surface, and zero elsewhere. Numerical results demonstrate that the radiation patterns depend critically on the frequency and source dimensions. For a noncompact source, the strongest radiation may not necessarily stem from a vibrating surface, but rather from a nonvibrating surface due to the effect of sound diffraction. The more noncompact the source is, the larger the number of side lobes in the near field and the more concentrated these side lobes will be. In the far field, however, the side lobes become smeared and less distinguishable. In other words, the effect of sound diffraction is greatly reduced in the far field. Source translational motion induces sound radiation in the perpendicular direction and enhances the radiated acoustic field in general. Enhancement in the forward direction is much greater than in the reverse direction.
A BOUNDARY INTEGRAL METHOD FOR ACOUSTIC SOURCE LOCALIZATION IN A WAVEGUIDE WITH INCLUSIONS
Authors: XU YONGZHI , YAN YI
Published: November 2004

In this paper, we continue our study on combining the matched field processing with the boundary integral equation (BIE) method of scattering theory to solve a sound source localization problem in a shallow ocean with a large inclusion which has a rigid boundary. We consider an enviroment where continuous waves (CW) are produced by a sound source, scattered by the inclusion, and then received by a hydrophone array. The symmetry of the waveguide is destroyed by the existence of the inclusion, and a proper procedure is therefore required to avoid the mismatching. We present a numerical scheme which makes use of the separation of the source and the detection array, and a BIE method. The separation greatly reduces the computation load. The BIE method preserves a certain accuracy on one hand and minimizes arithmetic operations on the other. Some numerical simulations using this scheme are presented.
A PE-BASED APPROACH TO MODAL DECOMPOSITION AND SOURCE LOCALIZATION
Authors: THOMSON DAVID J. , EBBESON GORDON R.
Published: November 2004

Matched mode processing is an efficient alternative to matched field processing for locating a source in an acoustic waveguide. The successful application of this method relies on the accurate modal decomposition of the pressure data received on a vertical line array. From the modes that can be resolved by a given array aperture, the source range is determined from modal phases, whereas the source depth is determined from the mode shapes. In this paper, we describe a decomposition method based on the parabolic equation (PE) propagation model for recovering this modal information from vertical array data and which can be used to localize an underwater source by the matched mode processing method. We apply our PE-based decomposition/localization scheme to several benchmark problems involving a narrowband acoustic source operating in a shallow water environment.
COMPUTATIONALLY EFFICIENT MONTE CARLO ESTIMATION ALGORITHMS FOR MATCHED FIELD PROCESSING IN UNCERTAIN OCEAN ENVIRONMENTS
Authors: SHOREY J. A. , NOLTE L. W. , KROLIK J. L.
Published: November 2004

In this paper, Monte Carlo estimation techniques are presented for computationally efficient implementation of two methods for matched field source localization in uncertain ocean channels. In the Optimal Uncertain Field Processor (OUFP), Monte Carlo integration is used to integrate out the environmental parameters and thus estimate the a posteriori distribution of the source location parameters. In the Minimum Variance Beamformer with Environmental Perturbation Constraints (MV-EPC), Monte Carlo estimation of the signal correlation matrix averaged over the ensemble of environmental realizations is used to estimate the beamformer constraints. Using the OUFP, detection performance bounds are evaluated which indicate that source position uncertainty affects performance much more than environmental uncertainty. An upper bound on source localization performance is also obtained indicating that for short observation times a threshold signal-to-noise ratio (SNR) exists, dependent upon environmental uncertainty, below which source localization performance rapidly degrades. Among robust minimum variance beamforming methods, the MV-EPC method demonstrated superior probability of correct localization (PCL), both in single source scenarios and in the presence of interference. The OUFP at high SNR and the MV-EPC at large observation times both achieved near perfect source localization performance, although for large environmental uncertainty the OUFP provides an upper bound on P CL .
MATCHED FIELD SOURCE LOCALIZATION WITH A HORIZONTAL LINE ARRAY
Authors: CHAPMAN N. R. , YEREMY M. L.
Published: November 2004

Matched field source localization performance is investigated for a source in aft endfire of a horizontal line array operating in a deep water environment. Simulations are used to investigate the performance for ideal conditions and in the presence of noise. In particular, the effects of uncertainty in experimental geometry and mismatch in sound speed profile are considered. It is shown that the performance is sensitive to the vertical tilt of the array for relatively small tilt angles of less than 5º.

However, the horizontal array is robust to mismatch in the gradient of the sound speed profile at the bottom of the water column. The results of the simulations are interpreted in terms of the characteristics of acoustic propagation in the environment.
SPIN WAVES IN BILAYER ISING-MODEL SYSTEMS IN A TRANSVERSE FIELD
Authors: SALMAN A. , COTTAM M.G.
Published: November 2004

Calculations are presented for the spin-wave excitations in some bilayer solid structures represented by the Ising Hamiltonian in a transverse field. The theory is applicable to real ferromagnetic materials with anisotropic exchange when placed in a transverse magnetic field, and also, within a pseudospin formalism, to order-disorder ferroelectrics. It is shown that there may be excitations localized near the surfaces and interface of the coupled magnetic system, depending on the parameters of the model, in addition to the modified bulk spin waves. Specific calculations are carried out for two special cases, namely, a ferromagnetic thin film and an interface between two different ferromagnetic media. The analytic results are illustrated by means of numerical examples.
THE Au(110) (2×1) SURFACE PHASE DIAGRAM AND (2×1) ORDERING AFTER GROWTH
Authors: BARBIER L. , SALANON B. , SPRÖSSER J.
Published: November 2004

The Au(110) surface has a (2×1) missing row reconstruction. Its temperature phase diagram is investigated by a Monte Carlo simulation. The comparison of MC calculations with equilibrium data shows that attractive interactions are very likely to be between steps of opposite sign. By depositing, at low temperature, 1/2 Au monolayer a new metastable (1×1) phase can be formed. The kinetics of the (2×1) ordering upon annealing is found to be slow and necessitates interlayer mass transport as shown by step formation. By depositing 1 Au monolayer, a mostly (2×1) disordered surface is created. Upon annealing the ordering process requires no step formation and occurs at a lower temperature.
DYNAMICAL EFFECTS IN REFLECTION HIGH-ENERGY ELECTRON DIFFRACTION INTENSITY OSCILLATIONS
Authors: ZHAO T.C. , IGNATIEV A. , Tong S.Y.
Published: November 2004

Intensity oscillations during MBE growth are simulated by periodic arrays of steps using dynamical multiple scattering theory of RHEED. Our results show that the oscillations depend strongly upon the scattering geometry. Phase effects, double periodicity, etc. observed in experiments can be explained within the framework of dynamical scattering. Conditions for which a simple interpretation of the oscillations can be made are also discussed.
LEED-AES STUDY OF SURFACE STRUCTURES FORMED AT COADSORPTION OF Al AND Sb ON (100), (111), AND (110) Si SURFACES
Authors: ZOTOV A.V. , RYZHKOV S.V. , LIFSHITS V.G. , DUCHINSKY V.G.
Published: November 2004

The formation of the ordered surface structures upon successive deposition of Al and Sb onto the Si(100), Si(111), and Si(110) surfaces held at about 650°C were studied by low-energy electron diffraction (LEED) and Auger electron spectroscopy (AES). The primary emphasis was given to the investigation of the formation of (Al, Sb)/Si interface at total coverages of adsorbates in submonolayer range. In this case, according to AES data the adsorption of Al and Sb atoms proceeds collaterally in a simple additive manner. In the LEED observations, several new reconstructions, Si (100)c(4×4), Si (100)2×8, Si(100)2×6, Si(111)2×2, [Formula: see text], and Si (110)3×4 which indicate the formation of the joint (Al, Sb)/Si surface phases were found. The conditions for the formation of the surface structures were summarized in the formation diagrams.
$\sqrt 3 \times \sqrt 3 $ RECONSTRUCTIONS OF Si(111) STUDIED BY SCANNING TUNNELING MICROSCOPY
Authors: NOGAMI JUN
Published: November 2004

Many different metals induce [Formula: see text] R30° reconstructions of the Si(111) surface. Although these surfaces share a common periodicity, they can have very different atomic structures. This paper discusses scanning tunneling microscope results and their relationship to the current understanding of the [Formula: see text] surface structure in several of these metal/Si(111) systems.
SURFACE ENHANCEMENT OF 3d, 4d, AND 5d IMPURITY MOMENTS AT Cu AND Ag(00l) SURFACES
Authors: STEPANYUK V.S. , LANG P. , WILDBERGER K. , ZELLER R. , DEDERICHS P.H.
Published: November 2004

We present ab initio calculations for the electronic structure of 3d, 4d, and 5d transition metal impurities at the (001) surface of Cu and Ag. Our focus is on the surface enhancement of the local impurity moments. The calculations are performed within local density functional theory and use a KKR Green's function method for impurities at surfaces. For 3d impurities we find a sizeable enhancement of the local moments, being most important for V and Cr. Extremely large effects are found for 4d and 5d impurities, which in general are nonmagnetic in the bulk. On the Ag(001) surface we find that Zr, Nb, Mo, Tc, Ru, Ta, W, Re, and Os are magnetic. Some of adatoms (Nb, Mo, Tc, W, Re) have "giant" magnetic moments between 3 and 4 μB.
REFLECTANCE ANISOTROPY OF THE GaAs(001) SURFACE
Authors: MORRIS S.J. , BASS J.M. , WESTWOOD D.I. , WOOLF D.A. , MATTHAI C.C. , WILLIAMS R.H. , REINHARDT F. , RUMBERG J. , ROSE K.C. , RICHTER W.
Published: November 2004

By a combination of theoretical calculations and experiments, we have investigated the GaAs(001) surface and found the reflectance anisotropy (RA) to be extremely sensitive to the atomic configuration upon the surface. By performing a series of ab initio pseudopotential calculations of the optical response of the (2×4) surface reconstruction we find that good agreement with experiment can be obtained when the full relaxation of the surface is taken into account. Experimentally, we show that deposition of as little as 0.01 monolayer of Si modifies the surface structure sufficiently that a significant change in the RA spectrum can be observed.
THE RELATIONSHIP BETWEEN REFLECTANCE ANISOTROPY AND ELECTRON DIFFRACTION IN THE DETECTION OF RECONSTRUCTION CHANGES OCCURRING AT III-V SEMICONDUCTOR SURFACES
Authors: ARMSTRONG S.R. , PEMBLE M.E. , TAYLOR A.G. , TURNER A.R. , FAWCETTE P.N. , JOYCE B.A. , NEAVE J.H. , ZHANG J.
Published: November 2004

We have utilised the technique of reflectance anisotropy (RA) to study the growth of GaAs, AlAs, and InAs on (001) GaAs substrates by molecular beam epitaxy and simultaneously recorded both the RA response and the surface electron diffraction pattern obtained using (RHEED). For macroscopic coverage variations the change in the RA response in all cases appears to correlate exactly with the appearance of a new RHEED pattern. In this respect RA growth "oscillations" are observed which correlate exactly in period with the usual RHEED oscillations observed during growth and can be made to be in-phase with the RHEED oscillations by varying the RHEED collection system. In the case of InAs growth, much more subtle (ca. 0.1 monolayers) coverage variations are easily detectable by RA while the macroscopic (2×4) to (4×2) phase transition which occurs for this system at InAs coverages of ca. one monolayer produces a marked change in both the RA and RHEED response. Since all three systems were studied using the same optical excitation energy (ca. 1.92 eV) and since in all cases the change in the RA response occurred concurrently with the change in the RHEED pattern we question the currently popular theory regarding the nature of the RA response in relation to a supposed local surface dimer state resonant absorption and suggest that geometric factors or longer range surface state resonances may be of equal if not more importance.
SURFACE ANISOTROPY OF SECOND HARMONIC GENERATION AT Al(111)
Authors: PETUKHOV A.V. , LIEBSCH A.
Published: November 2004

We present results of the first calculation of the surface anisotropic contribution to second harmonic generation for a realistic metal surface. Although the anisotropic second-order response has its origin at the surface, the main contribution to the surface anisotropic parameter ξ has a remarkably large penetration depth. Moreover, the long-range oscillations of the anisotropic nonlinear surface current deep inside aluminum are found. The surface anisotropic secondorder polarizability ξ is in a good qualitative agreement with recent experimental data on clean Al(111) at ħω=1.17 eV. A resonant enhancement of the SHG anisotropy is predicted for ω and 2ω close to 1.5 eV—the energy gap in bulk aluminum along the [100] directions. A significant decrease of the surface anisotropic response in comparison with the isotropic one is found for ω≥1.5 eV.
THE Cl/Si(100) INTERFACE OBSERVED BY ESDIAD AND RELATED TECHNIQUES
Authors: GUO Q. , STERRATT D. , WILLIAMS E.M.
Published: November 2004

The adsorption of chlorine on Si(100) surface has been studied using ESDIAD in conjunction with AES and gas uptake techniques. This work presents an extension of earlier studies of the adsorption of halogen gases at Si(100) which served to initiate our development of ESDIAD technique at the IRC. In the present instance, we report the findings in experiments with high-purity chlorine gas from a bottle, which is distinct from our earlier approach with an electrochemical cell for chlorine gas generation. Two types of adsorbate configurations which transform irreversibly are investigated.
OPTICAL SECOND-HARMONIC GENERATION FROM POROUS SILICON IN UHV
Authors: CAVANAGH M. , POWER J.R. , McGILP J.F. , MÜNDER H. , BERGER M.G.
Published: November 2004

The origin of the luminescence from porous Si (PS) is currently under intense scrutiny. Characterisation of this material on the atomic scale is difficult and optical techniques offer certain advantages. Ultrahigh vacuum studies of PS by optical second-harmonic generation (SHG) are presented. Excitation wavelengths corresponding to surface state and a suspected strain resonance from clean Si surfaces are used. Hydrogen-terminated and clean surfaces of Si(100) and PS are compared. The H-terminated surfaces give no signal under the excitation conditions used. On desorbing the hydrogen, a stable SH signal is obtained from the PS which has polarisation dependences different to those of clean Si(100), and which also differ between the surface and strain resonances.
UPS, XPS, AES STUDIES OF Te THIN FILMS DEPOSITED ON Si(100) 2×1
Authors: DI NARDO S. , LOZZI L. , PASSACANTANDO M. , PICOZZI P. , SANTUCCI S.
Published: November 2004

This work represents the first complete study of the interaction between Te and Si in very thin films of tellurium grown at room temperature on Si(100) 2×1 surfaces. In particular, the electronic properties have been investigated by UPS and XPS measurements and information on growth of tellurium on silicon have been obtained by AES measurements. Our results indicate that the interaction between tellurium and silicon is weak, taking the characteristic behavior of simple metals. Increasing the film thickness, the growth mode is one layer, completed with about 2 Å of Te nominal coverage, plus islanding, until the thickness reaches the value of about 10 Å, followed by coalescence of islands. When tellurium has completed a layer, the valence band surface states of silicon are quenched.
THE DYNAMICS OF DEUTERIUM ADSORPTION ON Pt{100} AND THE ROLE OF ADSORBATE-INDUCED DEFECTS
Authors: DIXON-WARREN ST. J. , PASTEUR A.T. , KING D.A.
Published: November 2004

The dissociative initial sticking probability, s0, for deuterium on Pt{100}-hex has been measured as a function of beam kinetic energy, Ek, and substrate temperature, T S . At TS=150 K, s was found to increase with increasing Ek consistent with direct activated adsorption; the increase is approximately linear. At Ek=0.063 eV , s0 is independent of substrate temperature (s0≈0.07) over the range 150 to 1000 K, also consistent with a direct adsorption process. We present evidence for an increase of s0 due to adsorbate-induced defects. These defects survive annealing to 500 K but do not survive annealing to 1030 K. We have also measured s for D 2 on the (1×1) bulk truncated surface, and find it to be similar to that for the hex-reconstructed phase.
STEP DYNAMICS ON VICINAL Al(11{2m+1}) SURFACES
Authors: GRAVIL P.A. , HOLLOWAY S.
Published: November 2004

The motion of steps on (113), (115), and (117) surfaces of aluminium has been studied by molecular dynamics simulations. The time dependence of the position fluctuations was found to show a power-law dependence, tn, where 0.25<n≤0.5. We conclude that step meandering occurs by the exchange of atoms between steps. For noninteracting steps this corresponds to a time exponent of n=0.5. The reduced time dependence is then due to the repulsion between the steps.
PHOTOEMISSION STUDIES OF THE Pt3Cr(110) SURFACE
Authors: PATEL R.B. , LIDDIARD A.J. , CRAPPER M.D.
Published: November 2004

Angle-resolved photoemission has been used to investigate the electronic structure of Pt 3 Cr . Experimental band structure has been calculated assuming a free-electron final state. Constant initial state measurements indicate that Pt and Cr d-bands both lie between the Fermi level and 7 eV binding energy.
THE ADSORPTION OF METHANOL ON WATER-PRECOVERED NiO/Ni{110}
Authors: SANDERS H.E. , GARDNER P. , KING D.A.
Published: November 2004

Methanol adsorbs onto water-precovered NiO surfaces with a change in geometry compared with monolayer adsorption with the C–O bond becoming more nearly perpendicular to the surface. The reorientation is presumably as a result of a maximisation of the hydrogen bonding interactions in the adlayer.
ELECTRONIC BAND STRUCTURES OF InAs(110) AND InAs(110)Bi(1 ML)
Authors: UMERSKI A. , SRIVASTAVA G.P.
Published: November 2004

We use a supercell technique with local density functional pseudopotential theory to calculate the self-consistent electronic band structures of InAs (110) with zero and one ordered monolayer coverage of Bi within the Goddard geometry. These systems have recently been the subject of experimental investigations by the McLean group, using angle-resolved photoemission spectroscopy. We are able to analyse the overlayer-induced states in terms of their energies, dispersions, and wave function characters, and our results are compared with the experimentally deduced observations. In addition we contrast our results for these materials with our earlier theoretical investigations of InAs (110) and InP (110) substrates with Bi overlayers. We are therefore able to confirm the experimental observation that the InAs(110)Bi(1 ML) has a relatively flat absorbate induced highest occupied state [in comparison to the GaAs(110)Bi(1 ML) system].
A NEW STUDY OF THE SURFACE ELECTRONIC STRUCTURE OF W(001)
Authors: HOOF JEROEN VAN , INGLESFIELD JOHN E. , COLLINS IAN
Published: November 2004

We have performed surface electronic structure calculations for W(001) using the surfaceembedded Green function technique. These calculations enable us to interpret angle-resolved photoemission spectra, which play an important role in the controversy over the surface reconstruction of W(001). We show that the state which, according to most theories, plays a key role in driving the reconstruction is apparently invisible in the photoemission spectra, because of its in-plane character.
Enhanced Arteriogenesis and Wound Repair in Dystrophin-Deficient
mdx
Mice
Authors: Straino Stefania , Germani Antonia , Di Carlo Anna , Porcelli Daniele , De Mori Roberta , Mangoni Antonella , Napolitano Monica , Martelli Fabio , Biglioli Paolo , Capogrossi Maurizio C.
Published: November 2004

Background—

The absence of functional dystrophin in Duchenne muscular dystrophy (DMD) patients and in
mdx
mice results in progressive muscle degeneration associated with necrosis, fibrosis, and inflammation. Because vascular supply plays a key role in tissue repair, we examined whether new blood vessel development was altered in
mdx
mice.

Methods and Results—

In a model of hindlimb ischemia on femoral artery dissection, hindlimb perfusion, measured by laser Doppler imaging, was higher in
mdx
mice (0.67±0.26) than in wild-type (WT) mice (0.33±0.18,
P
<0.03). In keeping with these data, a significant increase in arteriole length density was found in
mdx
mice (13.6±8.4 mm/mm
3
) compared with WT mice (7.8±4.6 mm/mm
3
,
P
<0.03). Conversely, no difference was observed in capillary density between mice of the 2 genotypes. The enhanced regenerative response was not limited to ischemic skeletal muscle, because in a wound-healing assay,
mdx
mice showed an accelerated wound closure rate compared with WT mice. Moreover, a vascularization assay in Matrigel plugs containing basic fibroblast growth factor injected subcutaneously revealed an increased length density of arterioles in
mdx
(46.9±14.7 mm/mm
3
) versus WT mice (19.5±5.8 mm/mm
3
,
P
<0.001). Finally, serum derived from
mdx
mice sustained formation of endothelium-derived tubular structures in vitro more efficiently than WT serum.

Conclusions—

These results demonstrate that arteriogenesis is enhanced in
mdx
mice both after ischemia and skin wounding and in response to growth factors.
Treating Osteoarthritis With Cyclooxygenase-2–Specific Inhibitors
Authors: Grover Steven A. , Coupal Louis , Zowall Hanna
Published: November 2004

Osteoarthritis and hypertension are highly prevalent among older Americans. Anti-inflammatory medications can destabilize blood pressure control. We estimated the decreased cardiovascular risk, premature mortality, and direct health care costs that could be avoided if blood pressure control is not destabilized among hypertensive Americans taking cyclooxygenase-2 (COX-2)–specific inhibitors for osteoarthritis. Data from the Third National Health and Nutrition Examination Survey (NHANES III) provided the distribution of cardiovascular risk factors among American adults with osteoarthritis and hypertension. The Cardiovascular Disease Life Expectancy Model was used to estimate the impact of a 2.26% increase in systolic blood pressure on the basis of results of a randomized trial comparing COX-2–specific inhibitors. A similar analysis was completed for American adults with osteoarthritis and untreated hypertension (≥140/90 mm Hg). Among 7.3 million Americans with treated hypertension, maintaining blood pressure control would avoid >30 000 stroke deaths and 25 000 coronary deaths resulting in >449 000 person years of life saved and $1.4 billion in direct health care cost savings. When an additional 3.8 million Americans with untreated hypertension are considered, maintaining blood pressure control could prevent >47 000 stroke deaths, 39 000 coronary deaths, and result in 668 000 person years of life saved and >$2.4 billion in direct health care cost savings. We conclude that even a small increase in systolic blood pressure among hypertensive Americans with osteoarthritis may substantially increase the clinical and economic burden of cardiovascular disease. Maintaining blood pressure control may be associated with substantial benefits.
Wine Production, Marketing and Consumption in the Ottoman Crimea, 1520-1542
Authors: Halenko Oleksander
Published: November 2004

This effort to estimate the amount of wine production in the Southern Crimea in the sixteenth century opens a window into the ways of accommodation of viticulture, wine production and wine commerce by the Ottoman Empire in a province with a predominantly Christian population. The terminology invented by the Ottomans to denote the taxes levied on viticulture reveals their highly sophisticated rationalistic approach, by which they settled the contradiction between the Islamic prohibition of wine and their practical interest in such a lucrative business, while tax rates developed on this basis granted a signi ficant tax break to Muslim viticulturers. The data of two extant Ottoman tax-registers for the Crimea show that such ingenious fiscal policy stimulated both Muslim investment in this business and conversion of local Christian peasants to Islam. Also, through data on the taxation of wine commerce, estimations of prices and tax rates for marketed wine were suggested. Cet essai d'estimer la quantité de vin produit en Crimée du sud au XVI e siècle ouvre en fait des perspectives sur l'adaptation de la viticulture, de la production et du commerce du vin par les Ottomans dans une province ayant une population principalement chretienne. La terminologie utilisée par les Ottomans pour la levée de taxe sur la viticulture révèle une approche rationnelle très so fistiquée, grace à laquelle avaint été résolue la contradiction existant entre la prohibition islamique du vin et l'intèrêt pratique pour une occupation lucrative. L'imposition qui s'est développée sur cette base accordait aux viticulteurs musulmans des allégements fiscaux signi ficatifs. Les données des deux registres de taxe existants montrent qu'une telle politique fiscale ingenieuse a apparement stimulé à la fois les investissements musulmans dans ce domaine et la conversion des paisans chrétiens locaux a l'islam. À travers les informations sur l'imposition du commerce du vin, des estimations de prix et de niveax d'imposition sur le vin mis en vente sont égalem, ent suggerés.
Vishwakarma Craftsmen in Early Medieval Peninsular India
Authors: Ramaswamy Vijaya
Published: November 2004

This article situates Vishwakarma craftsmen in the socio-economic milieu of early medieval Peninsular India. It seeks to analyse the dynamics of social change among craft groups with particular reference to the smiths, masons and carpenters constituting the Vishwakarma community. This is attempted by locating the dynamics of social change within the processes of temple building and urbanism in the Chola-Pallava period. The essay looks afresh at concepts like caste, guild and community in the speci fic context of technological and economic changes and craft mobility. In so doing the article cuts across conceptual categories in the light of empirical evidence. The study is based on epigraphic evidence, essentially from the Tamil country. Le présent article situe les artisans Vishwakarma dans le milieu socio-économique au début de la période médiévale de l'Inde péninsulaire. Il cherche à analyser la dynamique du changement social parmi les groupes d'artisans plus particulièrement les forgerons, maçons et menuisiers / ébénistes, bref ceux qui constituent la communauté Vishwakarma. Ce travail est effectué en situant la dynamique de l'évolution sociale au sein des divers processus de la construction des temples durant la période Chola-Pallava. L'article propose un nouveau regard sur les concepts tels que caste, association/corps de métier et communauté dans le contexte des progrès technologiques et économiques ainsi que la mobilité de l'artisanat. Cet essai va à l'encontre des catégories conceptuelles à la lumière des preuves empiriques. L'étude est basée sur des preuves épigraphiques du pays de Tamil Nadu.
A Randomized Crossover Study Investigating the Influence of Ranitidine or Omeprazole on the Pharmacokinetics of Cephalexin Monohydrate
Authors: Madaras‐Kelly Karl , Michas Patricia , George Molly , May Matthew P. , PhD Adeboye Adejare
Published: November 2004

Limited data characterize pharmacokinetic interactions between cephalexin and ranitidine, and no data exist for an interaction with proton pump inhibitors. The purpose of this study was to investigate the effects of ranitidine or omeprazole administration on the pharmacokinetics and pharmacodynamics of cephalexin. A randomized single‐ and multiple‐dose crossover study was conducted in healthy subjects ingesting cephalexin before and after steady‐state administration of ranitidine or omeprazole. Time‐concentration profiles were determined and pharmacokinetic parameters were characterized using noncompartmental methods. Pharmacokinetic data were analyzed in accordance with the two 1‐sided test for bioequivalence. The percentage of time that serum concentrations remain above the MIC90 during the dosing interval (T < MIC90) for Streptococcus pyogenes and Staphylococcus aureus associated with the pharmacokinetic profiles was calculated. The coadministration of cephalexin with ranitidine or omeprazole resulted in relatively minor changes in Cmax, AUC, t1/2, or CL/F. tmax was significantly prolonged when cephalexin was administered with ranitidine or omeprazole. Suboptimal T > MIC90 was observed for cephalexin irrespective of acid suppression. Delay in absorption of cephalexin resulted in a decrease in the percentage of T > MIC90 for certain acid‐suppressive regimens and pathogen combinations. With the exception of an increase in tmax, there were no significant pharmacokinetic interactions between cephalexin and ranitidine or omeprazole. Delayed tmax associated with acid suppression may result in a diminished T > MIC90.
Market Roll-Out and Retailer Adoption for New Brands
Authors: Bronnenberg Bart J. , Mela Carl F.
Published: November 2004

This paper proposes a descriptive model of the spatial and temporal evolution of retail distribution for new packaged goods. The distribution model postulates separate processes for local market entry by manufacturers, and adoption by retailers given entry. Of special interest is whether retail adoption occurs along a competitive network with retailers as nodes and overlapping trade areas of these retailers as links. The model is calibrated on data covering the introduction of two very successful new brands in the frozen pizza category. For these brands, manufacturers sequentially enter markets based on spatial proximity to markets already entered (spatial evolution), and on whether chains in these markets adopted previously elsewhere (market selection). A retail chain adopts new brands based on the adoption timing of competing chains within its trade territory (competitive contagion) and on the fraction of its trade area in which the new brand is available (trade area coverage). The effects of market selection and of trade area coverage create dependencies between market entry and retail adoption. Because of these dependencies the attraction of a particular market as a lead market depends on its location in the geographic structure of the U.S. retail trade.
Assistenzformen zur Erleichterung kontinuierlichen Weiterlernens (Assistance to Facilitate Continuous Learning)
Authors: Vogt Thomas , Kunze Stefan
Published: November 2004

Softwareanwendungen sind komplexe Systeme. Selbst erfahrene Anwender nutzen selten die ganze Leistungsfähigkeit eines Systems. Es ist wünschenswert, dass Nutzern nicht nur ein leichter Einstieg in ein System geboten wird, sondern dass sie auch in ihrem alltäglichen Umgang dabei unterstützt werden, kontinuierlich mehr über das System zu lernen. Dieser Aufsatz untersucht, wie Nutzer, die ein System bereits kennen, unterstützt werden können, um das angebotene Potential an Funktionalität besser auszuschöpfen. Dazu wird eine neue Klassifikation anwenderunterstützender Systeme vorgestellt, die v.a. die Entwicklung neuer Ansätze für die Unterstützung von Nutzern erleichtern soll. Der Office-Assistent von Microsoft wird als bekanntester Lösungsversuch betrachtet, und es wird eine praktische Umsetzung zeitverzögerter Nutzungshinweise für eine High-Traffic-Website beschrieben.
Ermittlung von Assistenzwünschen von Fahrern mit Hilfe der Methode Nutzer-Mock-Up (Finding out Drivers′ Requirements for Assistance by Means of User-Mock-Ups)
Authors: Enigk Holger , Polkehn Knut
Published: November 2004

In diesem Beitrag wird das Nutzer-Mock-Up als eine Methode des Benutzer-(Fahrer-)orientierten Entwurfs von Fahrerassistenzsystemen vorgestellt. Nach der Darstellung von Zielen und Konsequenzen des Einsatzes von Assistenzsystemen wird ein fahrerorientierter Ansatz zur Entwicklung von Fahrerassistenzsystemen beschrieben, der die Gestaltung von Assistenzsystemen im Rahmen der psychologischen Tätigkeitsgestaltung betrachtet. Die Methode „Nutzer-Mock-Up” kann schon im Vorfeld von Entwurfsentscheidungen der Erfassung von Vorstellungen der Nutzer dienen, so dass diese bereits in frühen Phasen der Entwicklung in den Entscheidungsprozess einbezogen werden.
Ist Sprachinteraktion heute schon intuitiv? (Is Speech Interaction Intuitive Today?)
Authors: Peissner Matthias
Published: November 2004

In einer empirischen Studie werden die Akzeptanz und Usability (Gebrauchstauglichkeit) von telefonbasierten Sprachapplikationen in Deutschland untersucht. Eine umfangreiche telefonische Befragung liefert Daten zur Nutzung und Akzeptanz von Sprachapplikationen. Detaillierte Erkenntnisse zur Gebrauchstauglichkeit aktueller Systeme und zu den relevanten Qualitätsaspekten der sprachlichen Benutzungsschnittstelle stammen aus Usability-Tests mit sechs ausgewählten deutschen Sprachapplikationen. Dieser Beitrag gibt einen Überblick über die wichtigsten Ergebnisse der Studie.
Barrierefreiheit im WWW (Web Accessibility)
Authors: Weber Harald , Mund Markus E. , Leidermann Frank , Zink Klaus J.
Published: November 2004

Der Beitrag dokumentiert den aktuellen Diskussionsstand zum Themenbereich Barrierefreiheit, bezogen auf die Nutzung von Web-Angeboten. Ausgehend einerseits von gesetzlichen Vorgaben, andererseits von einem modifizierten Verständnis von Usability, wird das Konzept Barrierefreiheit, wie es zur Zeit primär durch die Web Accessibility Initiative (WAI) des World Wide Web Konsortiums (W3C) geprägt ist, auch bzgl. Vollständigkeit und Weiterentwicklungsbedarf beleuchtet.
Self-reciprocal redundant vector stars
Authors: Gómez-Rodriguez A. , Aragón J. L. , Torres M.
Published: November 2004

In this work it is shown that a star of M vectors in Rn (M > n) is self-reciprocal, in the sense that it coincides with its Mackay generalized reciprocal star, if and only if it forms an eutactic star. We also show that eutactic stars behave in ways that resemble the behavior of orthonormal sets. A characterization of eutactic stars based on the Moore-Penrose pseudoinverse is presented.
Structural phase transitions in iodine under high pressure
Authors: Takemura Kenichi , Sato Kyoko , Fujihisa Hiroshi , Onoda Mitsuko
Published: November 2004

High-pressure powder X-ray diffraction experiments have been carried out on solid iodine at room temperature. A new intermediate phase V has been identified in the pressure range 24–28 GPa, in the close vicinity of the pressure-induced molecular dissociation. The structure is incommensurately modulated, a rare case for elemental solids. The nearest interatomic distances are distributed over a range 2.8–3.2 Å, which characterizes phase V as a transient state between the molecular and monatomic states. We discuss the overall change of the crystal structure of iodine with pressure, which gives an insight into the process of molecular formation and dissociation.
Incommensurate crystal structure of LiCd4(VO4)3
Authors: Gaudin Etienne , Yahia Hamdi B. , Shikano Masahiro , Amara Mongi B. , zur Loye Hans-Conrad , Darriet Jaques
Published: November 2004

Single crystals of LiCd4(VO4)3 were prepared by melting a powder sample of LiCd4(VO4)3 at 950 °C followed by slow cooling at 5 °C/hours down to room temperature. The crystal structure was determined by single crystal X-ray diffraction using the 4D superspace formalism. The superspace group is Cmcm(10γ) with unit cell parameters a = 5.8513(3) Å, b = 9.027(5) Å, c = 6.7721(7) Å and modulation vector q = a* + 0.7034c*. The LiCd4(VO4)3 structure is related to the Na2CrO4 structure type, which contains two independent tetrahedral sites that are occupied by sodium and chromium atoms and one octahedral site that is occupied by the second sodium atom. In the LiCd4(VO4)3 structure, the octahedral site is fully occupied by a cadmium atom, and one of the two tetrahedral sites is fully occupied by a vanadium atom. The second tetrahedral site is only partially filled: one third lithium, one third cadmium and one third vacant. To reflect the site occupancies, the overall formula can be expressed as Li1/3Cd1/3[ ]1/3CdVO4. One of the unusual features of the structure is the large anisotropy in the modulated occupancy of the tetrahedral site by lithium and cadmium. Structural relationships with the olivine structure type are discussed.
Patterns of Selection on Synonymous and Nonsynonymous Variants in Drosophila miranda
Authors: Bartolomé Carolina , Maside Xulio , Yi Soojin , Grant Anna L , Charlesworth Brian
Published: November 2004

We have investigated patterns of within-species polymorphism and between-species divergence for synonymous and nonsynonymous variants at a set of autosomal and X-linked loci of Drosophila miranda. D. pseudoobscura and D. affinis were used for the between-species comparisons. The results suggest the action of purifying selection on nonsynonymous, polymorphic variants. Among synonymous polymorphisms, there is a significant excess of synonymous mutations from preferred to unpreferred codons and of GC to AT mutations. There was no excess of GC to AT mutations among polymorphisms at noncoding sites. This suggests that selection is acting to maintain the use of preferred codons. Indirect evidence suggests that biased gene conversion in favor of GC base pairs may also be operating. The joint intensity of selection and biased gene conversion, in terms of the product of effective population size and the sum of the selection and conversion coefficients, was estimated to be ∼0.65.
Missense Mutations That Inactivate the Aspergillus nidulans nrtA Gene Encoding a High-Affinity Nitrate Transporter
Authors: Kinghorn James R , Sloan Joan , Kana'n Ghassan J M , DaSilva Edisio R , Rouch Duncan A , Unkles Shiela E
Published: November 2004

The transport of nitrate into prokaryotic and eukaryotic cells, of considerable interest to agriculture, ecology, and human health, is carried out by members of a distinct cluster of proteins within the major facilitator superfamily. To obtain structure/function information on this important class of nitrate permeases, a collection of chemically induced mutations in the nrtA gene encoding a 12-transmembrane domain, high-affinity nitrate transporter from the eukaryote Aspergillus nidulans was isolated and characterized. This mutational analysis, coupled with protein alignments, demonstrates the utility of the approach to predicting peptide motifs and individual residues important for the movement of nitrate across the membrane. These include the highly conserved nitrate signature motif (residues 166–173) in Tm 5, the conserved charged residues Arg87 (Tm 2) and Arg368 (Tm 8), as well as the aromatic residue Phe47 (Tm 1), all within transmembrane helices. No mutations were observed in the large central loop (Lp 6/7) between Tm 6 and Tm 7. Finally, the study of a strain with a conversion of Trp481 (Tm 12) to a stop codon suggests that all 12 transmembrane domains and/or the C-terminal tail are required for membrane insertion and/or stability of NrtA.
Kikuchi-Fujimoto Disease With Prolonged Fever in Children
Authors: Lee Kyung-Yil , Yeon Yeong-Heum , Lee Byung-Churl
Published: November 2004

We reviewed 12 patients who had Kikuchi-Fujimoto disease (KFD) and presented with prolonged fever and lymphadenopathy. The clinical and laboratory aspects of the patients confirmed by excisional lymph node biopsy were analyzed. The mean age of the children was 11.0 ± 3.0 years (range: 6–15 years). The male-to-female ratio was 1.4:1. The median duration of fever before admission and the total duration of fever was 13 days (range: 7–65 days) and 19.5 days (range: 9–75 days), respectively. One patient had supraclavicular lymphadenopathy, 10 had cervical involvement, and 1 had axillary lymphadenopathy. All of the histologic findings of the lymph node biopsies showed the characteristic findings consistent with KFD, such as paracortical necrosis with karyorrhexis and an increase in the number of phagocytic histiocytes and atypical lymphocytes. As for the laboratory findings, leukopenia (3600 ± 900 per mm3), anemia (hemoglobin 11.4 ± 1.2 g/dL), an elevated erythrocyte sedimentation rate (44 ± 18 mm/hour), and a relatively low C-reactive protein level (1.3 ± 1.1 mg/dL) were noted. Eight patients received conservative therapy with antipyretics, and 3 patients were treated with prednisolone. KFD is a rare disease yet should be considered in the differential diagnosis for older children with prolonged fever and lymphadenopathy.