bluuebunny/crossref_metadata_2025 huggingface dataset:
PERIODIC WINDOWS INSIDE CHAOS — EXPERIMENT VERSUS THEORY
Authors: BRAUER ECKART , BLOCHWITZ STEFAN , BEIGE HORST
Published: November 2004

A series resonance circuit that consists of a linear inductance, a nonlinear capacitance and a sinusoidal driving is investigated. The nonlinearity arises from a ferroelectric crystal. We observed the Feigenbaum scenario, crises, periodic windows inside chaos that show a period adding behaviour and coexisting attractors of different symmetry. We conclude a Duffing equation to cover all significant properties of our dynamical system.
VARIATION OF LYAPUNOV EXPONENTS ON A STRANGE ATTRACTOR FOR SPIKING LASER OSCILLATION
Authors: OTSUKA KENJU , CHERN JYH-LONG
Published: November 2004

We analyze temporal variations in local Lyapunov exponents for chaotic spiking lasers in terms of standard deviation and Allan variance as a function of integral time τ. We show that standard deviations for local Lyapunov exponents become saturated in short τ regimes. The calculated Allan variance and power spectrum analysis suggest that the transition between stationary and nonstationary chaos takes place around the relaxation oscillation period of lasers, and that local Lyapunov exponents become nonstationary in time in the short τ regime.
SYNERGETICS: FROM PATTERN FORMATION TO PATTERN ANALYSIS AND PATTERN RECOGNITION
Authors: HAKEN HERMANN
Published: November 2004

It is by now well known that numerous open systems in physics (fluids, plasmas, lasers, nonlinear optical devices, semiconductors), chemistry and biology (morphogenesis) may spontaneously develop spatial, temporal or spatiotemporal structures by self-organization. Quite often, striking analogies between the corresponding patterns can be observed in spite of the fact that the underlying systems are of quite a different nature. In this paper I shall first give an outline of general concepts that allow us to deal with the spontaneous formation of structures from a unifying point of view that is based on concepts of instability, order parameters and enslavement. We shall discuss a number of generalized Ginzburg-Landau equations. In most cases treated so far, theory started from microscopic or mesoscopic equations of motion from which the evolving structures were derived.

In my paper I shall address two further problems that are in a way the reverse, namely

(1) Can we derive order parameters and the basic modes from observed experimental data?

(2) Can we construct systems by means of an underlying dynamics that are capable of producing patterns or structures that we prescribe?

In order to address (1), a new variational principle that may be derived from path intergrals is introduced and illustrated by examples. An approach to the problem (2) is illustrated by the device of a computer that recognizes patterns and that may be realized by various kinds of spontaneous pattern formations in semiconductors and lasers.
PATTERN SELECTION IN BÉNARD-MARANGONI CONVECTION
Authors: BESTEHORN MICHAEL
Published: November 2004

Pattern formation in fluids with a free flat upper surface is examined. On that surface, the Marangoni effect provides an additional instability mechanism. Based on amplitude equations it is shown that phase instabilities confine the region of stable hexagons to a narrow band of wavelengths. On the other hand we developed a numerical scheme that allows for a direct integration of the fully three-dimensional hydrodynamic equations. There we show the evolution of random patterns and the creation and stabilization of defects as well as the instability of hexagonal patterns lying outside the stable band of wave vectors.
LARGE-SCALE DISTORTIONS OF SQUARE PATTERNS
Authors: NEPOMNYASHCHY ALEXANDER
Published: November 2004

Stationary square patterns are typical in several instability problems. Near the instability threshold, the evolution of long-wave disturbances can be described by a system of amplitude equations resembling the Newell-Whitehead-Segel equations. These equations are used for the linear stability analysis and the investigation of the defects.
VARIOUS WAVE PHENOMENA DURING THE OSCILLATORY ELECTRODISSOLUTION OF COBALT
Authors: OTTERSTEDT R.D. , JAEGER N.I. , PLATH P.J.
Published: November 2004

Experimental studies have been carried out with disk-like cobalt sheets in unstirred diluted phosphoric acid under potentiostatic control. Voltages were chosen such that oscillations of the integral current indicating transitions between the active and the passive state of the metal occurred. Spatiotemporal patterns during these transitions, visible due to changes of the reflectivity of the surface, were recorded with a video camera. High-amplitude periodic relaxation oscillations of the integral current are linked to the accelerated propagation of activation waves covering the whole electrode surface. Low-amplitude aperiodic oscillations of the integral current are associated with propagation in a series of pulses, i.e., accelerating and decelerating waves. Often, the stepwise propagating waves emit during acceleration another wave backwards. Annihilation of waves was also observed.
BOUNDARY DOMINATED VERSUS BULK DOMINATED REGIME IN OPTICAL SPACE-TIME COMPLEXITY
Authors: ARECCHI F.T. , BOCCALETTI S. , GIACOMELLI G. , PUCCIONI G.P. , RAMAZZA P.L. , RESIDORI S.
Published: November 2004

By increasing the aspect ratio of an optical cavity with a photorefractive crystal, we observe the transition from a boundary-controlled regime, where the size of the transverse patterns scales with the aspect ratio, to a bulk-controlled regime where the pattern size is independent of the aspect ratio. In this new regime, the size corresponds to an intrinsic correlation length imposed by diffusion processes within the material. Such a new behavior is explained by the wave-number dependence of the gain within the instability region. Model equations provide good agreement with the two asymptotic cases of small aspect ratio (diffraction limited regime) and large aspect ratio (diffusion limited regime).
EXPERIMENTAL RESULTS ON DEFECTS IN ONE-DIMENSIONAL HEATING PATTERNS
Authors: MAZA-OZCOIDI D. , BURGUETE J. , MANCINI H.L.
Published: November 2004

A liquid layer under one-dimensional heating suffers a transition from convective rolls to a pattern where a second mode is present. This pattern has three main regimes, i.e., stationary, travelling and oscillatory. Here we describe the defects that appear in the travelling regime. Two kinds of dynamics can show up depending on the thermal characteristics of the boundaries: cores of defects (sources and sinks) or defects that spread over the whole pattern.
INFLUENCE OF DEFECTS IN THE HEXAGON-ROLL TRANSITION IN CONVECTIVE LAYERS
Authors: MILLÁN-RODRÍGUEZ JUAN
Published: November 2004

We investigate numerically the structure of the boundaries between domains of hexagons arising in a convective system when the vertical symmetry is broken. The wall is basically formed by penta-hepta (P-H) pair defects. The transition from a pattern of hexagons to rolls begins just at the core of the defect and moves in the direction of the roll belonging to the defect structure.
CHARACTERIZATION OF HOMOCLINIC CHAOS IN A GLOW DISCHARGE THROUGH RETURN MAPS
Authors: BRAUN THOMAS , LISBÔA JORGE A.
Published: November 2004

We show that homoclinic chaos in the current of a DC electrical discharge is easily characterized through return maps. We derive the same information from a Poincaré section map, a time-of-flight map, and a next maximal amplitude map. The presence of a homoclinic orbit in the phase space of our system is responsible for the equivalence of the three kinds of return maps.
GLOBAL ASYMPTOTIC BEHAVIOR OF ITERATIVE IMPLICIT SCHEMES
Authors: YEE H.C. , SWEBY P.K.
Published: November 2004

The global asymptotic nonlinear behavior of some standard iterative procedures in solving nonlinear systems of algebraic equations arising from four implicit linear multistep methods (LMMs) in discretizing three models of 2×2 systems of first-order autonomous nonlinear ordinary differential equations (ODEs) is analyzed using the theory of dynamical systems. The iterative procedures include simple iteration and full and modified Newton iterations. The results are compared with standard Runge-Kutta explicit methods, a noniterative implicit procedure, and the Newton method of solving the steady part of the ODEs. Studies showed that aside from exhibiting spurious asymptotes, all of the four implicit LMMs can change the type and stability of the steady states of the differential equations (DEs). They also exhibit a drastic distortion but less shrinkage of the basin of attraction of the true solution than standard nonLMM explicit methods. The simple iteration procedure exhibits behavior which is similar to standard nonLMM explicit methods except that spurious steady-state numerical solutions cannot occur. The numerical basins of attraction of the noniterative implicit procedure mimic more closely the basins of attraction of the DEs and are more efficient than the three iterative implicit procedures for the four implicit LMMs. Contrary to popular belief, the initial data using the Newton method of solving the steady part of the DEs may not have to be close to the exact steady state for convergence. These results can be used as an explanation for possible causes and cures of slow convergence and nonconvergence of steady-state numerical solutions when using an implicit LMM time-dependent approach in computational fluid dynamics.
SIMPLE HYBRID SYSTEMS
Authors: JOHNSON STEWART D.
Published: November 2004

A hybrid system is one which can instantaneously switch between a number of phase portraits. Switching occurs when trajectories hit prescribed switching curves. This type of system is highly applicable to digital controls such as robotic controls. A working definition of such a system is given, as well as a method for stabilizing periodic orbits and several examples.
C2, C3AND C4-MOVES AND THE COEFFICIENT OF THE CONWAY POLYNOMIAL FOR KNOTS
Authors: YAMADA HARUMI
Published: November 2004

We consider how Cn-move has an influence on the Vassiliev invariant of order m. In other words, we investigate the variance of the value of concrete Vassiliev invariant of order m by a Cn-move. We choose the mth coefficient of the Conway polynomial, am, as a concrete Vassiliev invariant of order m, and study the variance of that by a Cn-move for n≤4. And we get that when we give a natural number k, there is a pair of knots satisfying that they are transformed into each other by a Cn-move and the difference of amof them is equal to k in almost case under the condition that n<m and n≤4.
BIRMAN'S CONJECTURE FOR SINGULAR BRAIDS ON CLOSED SURFACES
Authors: PARIS LUIS
Published: November 2004

Let M be a closed oriented surface of genus g≥1, let Bn(M) be the braid group of M on n strings, and let SBn(M) be the corresponding singular braid monoid. Our purpose in this paper is to prove that the desingularization map η : SBn(M)→ℤ[Bn(M)], introduced in the definition of the Vassiliev invariants (for braids on surfaces), is injective.
A HIGH RESOLUTION FINITE ELEMENT ANALYSIS FOR NONLINEAR ACOUSTIC WAVE PROPAGATION
Authors: SHEU TONY W. H. , FANG C. C.
Published: November 2004

We investigate the application of Taylor Galerkin finite element model to simulate the propagation of impulse disturbances governed by the nonlinear Euler equations. This formulation is based on the conservation variables rather than the primitive variables so that the slowly emerging sharp acoustic profiles due to the initial fluctuation can be sharply captured. We show that when the generalized Taylor Galerkin finite element model is combined with the flux corrected transport technique of Boris and Book, the acoustic field can be more accurately predicted. The proposed prediction method was validated first by simulating different classes of transport profiles before applying it to investigate the truly nonlinear acoustic field emanating from an initial square pulse.
EXACT, NONREFLECTING BOUNDARY CONDITIONS FOR PARABOLIC-TYPE APPROXIMATIONS IN UNDERWATER ACOUSTICS
Authors: PAPADAKIS JOHN S.
Published: November 2004

In the different parabolic approximations to the reduced wave equation which model acoustic propagation in the ocean, the bottom is usually modeled as an interface and the domain of propagation includes an absorbing layer below the bottom interface. Thus the boundary value problem to be solved has zero boundary conditions at the surface as well as at the bottom boundary. In this paper exact boundary conditions are developed and numerically implemented along the physical bottom boundary if it is horizontal, otherwise, along an artificially placed horizontal computational boundary inside the bottom. These boundary conditions are nonlocal but integrable and can be incorporated in finite difference schemes for the parabolic equations.
BOTTOM SCATTERING IN ACOUSTIC PROPAGATION MODELING
Authors: PURRINGTON R. D.
Published: November 2004

The problem of propagating acoustic energy in the ocean subject to boundary roughness is considered. Both a small range-step "Monte-Carlo" approach, in which the acoustic signal is scattered from an ocean bottom consisting of the deterministic bathymetry with a stochastic component superimposed, and a scattering kernel method, in which the pressure field vector is analyzed at each range step and modified by the application of a scattering operator, are discussed. Results of computations using the former are presented. A higher-order, energy-conserving, finite-element parabolic-equation model is used.
THE MATCHED FIELD PROCESSING BENCHMARK PROBLEMS
Authors: PORTER MICHAEL B. , TOLSTOY A.
Published: November 2004

In matched field processing sophisticated acoustic models are combined with signal processing techniques to localize an acoustic source in the ocean. A key challenge has been to develop schemes that work not just in idealized simulations but in realistic scenarios. Additionally it has been difficult to get a sense of the relative merits of different schemes: there has been no common set of problems to test the techniques. To assess the state of the art, a workshop was held in May 1993 at the Naval Research Laboratory where both simulated and experimental data were provided to the community of users to test the algorithms. However, researchers were not given the true source location and thus exercised their algorithms blindly. We describe here the test problems and provide an overview of the results and the lessons learned.
PERFORMANCE STUDY OF A MINIMAX ROBUST MATCHED FIELD PROCESSOR
Authors: GERR NEIL L. , GINGRAS DONALD F.
Published: November 2004

In both conventional array processing, where wave front arrivals are assumed planar, and matched field processing, where full field propagation models are used to predict the signal field at the array, detection and localization are carried out by looking for large values of the beamformer response. This approach does not generally model the statistical uncertainty in the signal wave front arrival structure that results from fundamentally stochastic ocean environmental phenomena. The realization that, inevitably, the true environment differs from that used to generate the predicted signal field has motivated interest in robust matched field processors. In a recent paper, we showed how one may adapt the minimax solution to the uncertain communication channel equalization problem to derive robust matched field processors. In this paper we discuss some of the acoustic and computational issues associated with these robust matched field processors and describe the results obtained upon applying these processors to the Acoustic Models in Signal Processing (AMSP) Workshop test data sets.
THE EFFECT OF OCEAN CURRENT ON SOUND PROPAGATION
Authors: GRIGORIEVA NATALIE S.
Published: November 2004

The effect of medium motion on sound propagation in the ocean is investigated. In a moving fluid, the sound propagation is described by a system of seven linear partial differential equations for seven unknown elements of a sound wave. These are the sound pressure, the particle oscillation velocity in a sound wave as well as the changes of medium density, its entropy, and concentration of the salt caused by passage of a sound wave. In the case of stratified moving medium, the point source field is represented in the form of a sum of quasinormal waves. If the ocean perturbed by a current is weakly inhomogeneous along the horizontal direction, the modification of the well-known method of horizontal rays/vertical modes is used. The "effective" sound speed for the model of stratified ocean is introduced. It allows the qualitative estimation of the medium motion effect on sound propagation taking into account the deformation of the initial sound speed profile. A sequence of direct numerical simulations of sound propagation problems has been carried out for the Gulf Stream models. It is shown that a large-scale current may alter the nature of guided wave sound propagation. For example, a current may lead to noticeable strengthening of a near surface waveguide. It results in smoothed field pattern and significant illumination of the shadow zones. Taking account of the medium inhomogeneity along the horizontal direction leads to the shift of the shadow zones and the illuminated domains relative to the source. If a sound path crosses the Gulf Stream ring, the medium motion effect on sound propagation may be ignored.
FILMS IN TETRAGONAL STATES PRODUCED BY EPITAXIAL STRAIN
Authors: MARCUS P.M. , JONA F.
Published: November 2004

The tetragonal states of {001} films of cubic materials produced by coherent epitaxy on cubic {001} substrates are calculated for Cu and Fe assuming Poisson ratios for the bcc and fcc structures that are constant as the material deforms. The states lie on lines, referred to as epitaxial lines, on the plane, referred to as the tetragonal plane, whose axes are the aspect ratio c/a and volume per atom V. The results of quantitative low-energy electron diffraction (QLEED) for the bulk layer spacing of coherent epitaxial films of Cu and Fe, when plotted on the tetragonal plane, show whether the films lie on the bcc or fcc epitaxial line. Strain-energy calculations along the epitaxial lines lead to a critical value of a at which a first-order transition from one epitaxial line to the other occurs; this transition is illustrated by the epitaxial films of Fe, some of which lie on the bcc line and some on the fcc line.
CAN WE "MEASURE" A POTENTIAL ENERGY SURFACE FOR A GAS-SURFACE SYSTEM?
Authors: HOLLOWAY S. , DARLING G.R.
Published: November 2004

One of the prime motivations for performing experimental studies of dynamical processes at the gas-solid interface is to increase our understanding of the microscopic forces that govern the molecular motion. In this review we examine the links between scattering and adsorption probabilities and potential energy surfaces that have been obtained from all electron total energy calculations. To make the link it is necessary to perform large scale molecular simulations. Examples are presented for two different sorts of processes giving rise to dissociative adsorption: one in which a molecular state occurs and the other being direct dissociation. We comment on the state-of-the-art potential energy calculations and show that there are still some problems in calculating the absolute energetics of dissociation but that it may be possible to calculate reliable reaction paths and topologies.
STICKING IN THE PHYSISORPTION WELL: H2 AND D2 ON COPPER
Authors: PERSSON M. , ANDERSSON S.
Published: November 2004

In this brief overview we address, with specific reference to the systems H 2 and D 2 on Cu(111), Cu(100), and Cu(110), several matters concerning the sticking of light particles in a physisorption well. These are considered in relation to observations from molecular beam scattering experiments and theoretical model calculations.
EPITAXIAL GROWTH OF Au ON Pt(011) STUDIED WITH X-RAY PHOTOELECTRON DIFFRACTION
Authors: STUCK A. , FASEL R. , OSTERWALDER J. , SCHLAPBACH L.
Published: November 2004

Au films 0.24 to 5.9 monolayers thick were evaporated on Pt(011), and the growth mode was investigated with X-ray photoelectron diffraction. At 0.5 monolayer coverage most Au atoms are found in the second layer below the surface while a few atoms diffuse as far as four layers deep even though Au is not miscible with Pt in the bulk at low concentrations. With increasing coverage the missing rows of the Pt(011) (2×1) reconstruction are gradually filled by replaced Pt atoms and further Au atoms, but the top layer relaxation is not changed significantly. At high coverages Au grows epitaxially as Au(011) on the Pt(011) surface and exhibits a poorly developed missing-row reconstruction.
IMAGE-INDUCED SURFACE STATES AND RESONANCES AT Fe(110)
Authors: NEKOVEE MAZIAR , INGLESFIELD JOHN E.
Published: November 2004

In this paper image-induced surface states at metal surfaces will be discussed, and the transition from image states to image resonances in those cases where they disperse into the bulk continuum. The behavior is particularly interesting in the case of Fe(110) where the spin-split image states disperse into the spin-split continua and show different surface resonance behavior. The surface state-surface resonance transition can be simply understood in terms of an embedding potential which describes their interaction with the crystal.
PROBING SURFACES AND INTERFACES WITH OPTICAL TECHNIQUES
Authors: ZAHN DIETRICH R.T.
Published: November 2004

The potential of optical techniques for probing semiconductor surfaces and interfaces is discussed using the example of Raman spectroscopy. The surface sensitivity of the technique is demonstrated by the detection of vibrational modes of atomic monolayers on semiconductor substrates, for instance arsenic on silicon(111). The special feature of Raman spectroscopy, namely its chemical sensivity, is illustrated by two examples: the interdiffusion of group III overlayers, e.g., In on the group V substrate Sb and the detection of reacted layers at II–VI/III– V heterointerfaces. The example of II–VI/III–V heteroepitaxy also serves as an example for demonstrating the growth monitoring capabilities of optical techniques.
SECOND-HARMONIC GENERATION AT SURFACES
Authors: CINI MICHELE
Published: November 2004

A method for computing the intensity of electric dipole second-harmonic generation from semiconductor surfaces and interfaces is presented. It uses third-order perturbation theory and a Green's function technique to embody Fresnel's formulas. Calculations for As/Si(111) are compared to experimental data, and show fair agreement for the spectral and angular dependence of the second-harmonic signal; the calculated absolute intensity, however, is too high. To investigate the origin of the discrepancy, we generalize the theory to all orders in the electron-photon coupling. The new scheme, based on the method of excitation amplitudes, is outlined. It allows to set up a theory of the second-harmonic generation response and other inelastic light scattering phenomena, like the dynamical Stark effect. Many-photon effects can modify the response in a qualitative way, and the maximum intensity of the second-harmonic fields does not generally correspond exactly to twice the incident frequency. This formalism also leads to new exact sum rules for nonlinear optics, that complement those obtained recently by Bassani and Scandolo.
CATALYSIS BY METALS: FROM EXTENDED SINGLE CRYSTALS TO SMALL CLUSTERS
Authors: GOODMAN D.W.
Published: November 2004

Model oxide-supported metal cluster catalysts have been prepared by evaporating the corresponding metal (e.g., Cu, Pd, Ni) onto a oxide thin film (~100 Å), which in turn is supported on a refractory metal (Mo, W, Ta) surface. The deposited metal films, upon annealing, form small metallic clusters on the oxide surface whose size are dependent upon the initial metal film thickness. The surface structures and cluster morphologies have been characterized using scanning probe microscopies, temperature-programed desorption, X-ray, and ultraviolet photoemission; and high-resolution electron energy loss spectroscopy/infrared reflection-absorption spectroscopy of adsorbed carbon monoxide. The catalytic properties of these clusters have also been investigated with respect to several reactions including CO/O 2 and CO/NO. The chemical and electronic properties of the metal clusters with respect to size are compared to the analogous properties of extended single crystal surfaces.
POSSIBLE "HOT" MOLECULE DESORPTION BY ELECTRON STIMULATED DECOMPOSITION OF DIHALOETHANES ON Cu(111)
Authors: TURTON S. , KADODWALA M. , JONES ROBERT G.
Published: November 2004

The desorption of ethene from physisorbed 1, 2-dichloroethane (DCE) and 1-bromo-2-chloroethane (BCE) on Cu(111) has been observed on irradiating the surface with electrons. The techniques used were low energy electron diffraction (LEED), Auger electron spectroscopy (AES), ultraviolet photoelectron spectroscopy (UPS), and mass spectrometric detection of the desorbed species. At 110 K physisorbed DCE and BCE underwent electron capture from low energy (<1 eV ) electrons in the secondary electron yield of the surface followed by decomposition and desorption of ethene alone. The decomposition was found to be first order in the surface coverage of the physisorbed DCE/BCE. No other molecular species desorbed from the surface, a stoichiometric amount of chemisorbed halogen was deposited and no carbon was detectable at the end of the desorption. The formation of the negative ions of these molecules by electron capture of low energy electrons in the secondary electron emission from the surface and the possible dynamics by which the negative ions undergo decomposition leaving the ethene product with sufficient energy to desorb, are discussed.
DISSOCIATIVE ADSORPTION OF NO AND REACTIONS OF NO2 ON ROUGH SILVER SURFACES
Authors: BARTOLUCCI F. , OTTO A.
Published: November 2004

The transformation of NO and NO 2 on cold-deposited silver films (30-40 K) has been investigated by SERS under UHV conditions. After exposure with doses of NO we observed strong signals of [Formula: see text], N 2O, and atomic oxygen and weak signals of physisorbed N 2 but none of NO. The reactions of NO 2 on the surface are exposure dependent and yields the formation of [Formula: see text], [Formula: see text], and the dimerised species N 2O4.
EFFECTS OF SUB-MONOLAYER COVERAGES OF OXYGEN ON THE 4f LINESHAPES OF CERIUM COMPOUNDS
Authors: BLYTH R.I.R. , ANDREWS A.B. , ÁRKO A.J. , JOYCE J.J. , CANFIELD P.C. , FISK Z. , LAHIASE U.G.L. , DELONG L.
Published: November 2004

Resonant photoemission at the Ce 4D edge has been used to investigate the effects of small doses of oxygen on the 4f lineshapes of CeAl, CeSn 3, CeCu 2 Si 2, CeBe 13, CeSi 2, and CeSb 2. In general we find that the Fermi level 4f peak is rapidly quenched, while the "2 eV" peak intensity increases, consistent with the formation of Ce 2 O 3 and possibly ternary oxides. We conclude that surface 4f features are a major part of the clean spectrum, and that sample purity is paramount when attempting to obtain data suitable for comparison with theory. Using the example of CeCu 2 Si 2 we show how previously published data, which has recently been used to show the supposed validity of the Kondo approach, were in fact obtained from oxidised samples.
ELLIPSOMETRIC STUDIES OF VERY LOW PRESSURE THERMAL CVD GROWN SILICON NITRIDE THIN FILMS USING HYDRAZOIC ACID AND DICHLOROSILANE
Authors: BRIDGES A.S. , GREEF R. , JONATHAN N.B.H. , MORRIS A. , PARKER G.J.
Published: November 2004

High quality silicon nitride thin films have been grown using dichlorosilane and hydrazoic acid (ratio 1:5) at a total ambient growth pressure of 1×10–4 Torr. Sequential growth studies of successive CVD nitride films over the 974-1068 K temperature range revealed an activation energy of 84 kJmol –1. Film thicknesses and refractive indices were obtained using in situ real-time ellipsometry, and the majority of the grown films displayed a refractive index of 2.0. Ellipsometric data for the growth of an 8 Å thermal-nitride film with a refractive index of 2.0 are also given.
A COMPARATIVE STUDY OF THE SODIUM-PROMOTED OXIDATION AND NITRIDATION OF Si(100)-(2×1) USING O2 AND N2 MOLECULAR BEAMS
Authors: BUSH T.L. , JONES T.S. , HAYWARD D.O.
Published: November 2004

The interaction of O 2 and N 2 molecular beams with a Na-covered Si(100)-(2×1) surface has been studied as a function of incident beam energy and sodium coverage. Exposure to O 2 at 300 K results in the immediate dissociation of the molecules on impact with the surface leading to the direct formation of silicon oxide. In contrast, significant nitridation requires a further step involving desorption of the sodium. The rate of formation of the oxide or nitride increases uniformly with sodium coverage. In addition, the reaction probability for both processes is significantly enhanced by increasing the translational energy of the incident O 2 or N 2 molecules. These observations indicate that both reactions proceed via a direct collisional activation process in which local electrostatic forces in the vicinity of the Na atoms are responsible for the promotional effect.
AN STM STUDY OF THE (2×4) AND c(4×4) RECONSTRUCTIONS FORMED ON GaAs(001) BY MOLECULAR BEAM EPITAXY
Authors: AVERY A.R. , HOLMES D.M. , JONES T.S. , JOYCE B.A.
Published: November 2004

Atomic resolution scanning tunneling microscopy (STM) has been used to study the Asterminated (2×4) and c(4×4) reconstructions formed on GaAs(001) surfaces grown in situ by molecular beam epitaxy (MBE). Filled states STM images of the (2×4) surface always showed unit cells consisting of two As dimers in the top layer. Cooling this surface under an As flux led initially to a highly kinked (2×4) phase before the transition to the c(4×4) structure. At no point were three As dimers observed in the top layer for the (2×4) unit cell. The c(4×4) structure involves the chemisorption of a second layer of As onto an already As-terminated surface. STM images of this surface showed a series of bright rectangular blocks consisting, when complete, of three pairs of As atoms.
COMBINED USE OF QUANTITATIVE LEED AND STM ON Cu(100)-c(2×2)N SURFACES
Authors: DHESI S.S. , BARRETT S.D. , ROBINSON A.W. , LEIBSLE F.M.
Published: November 2004

Quantitative low-energy electron diffraction (LEED) has been used in conjunction with Scanning Tunneling Microscopy (STM) to demonstrate that these two techniques are complementary and that quantitative LEED can be used in surface analysis without the need for computationally intensive theoretical calculations. We present LEED intensity-voltage (I-V) curves from Cu (100)-c(2×2) N surfaces and make qualitative comparisons with quantitative LEED data that exists in the literature. The implications of these comparisons are discussed with respect to other studies of this system.
THE INTERACTION OF METHANOL WITH CLEAN AND OXYGEN-PRECOVERED Ag{111}: A RAIRS STUDY
Authors: SIM W.S. , GARDNER P. , KING D.A.
Published: November 2004

The adsorption of methanol on clean and oxygen-precovered Ag{111} has been investigated by high-resolution infrared spectroscopy. On the clean surface a highly inclined, associatively adsorbed methanol overlayer was detected. The presence of coadsorbed atomic oxygen results in the formation of a surface methoxy species, which is shown to have its C-O bond axis oriented normal to the surface by the application of the metal-surface selection rule.
High-Density Lipoprotein Stimulates Myocardial Perfusion In Vivo
Authors: Levkau Bodo , Hermann Sven , Theilmeier Gregor , van der Giet Markus , Chun Jerold , Schober Otmar , Schäfers Michael
Published: November 2004

Background—

Several clinical studies have demonstrated a close association between plasma HDL cholesterol levels and endothelium-dependent vasodilation in peripheral arteries. In isolated arteries, HDL has been shown to mediate vasodilation via NO release. In vivo, administration of reconstituted HDL restored abnormal endothelial function of the brachial artery in hypercholesterolemic patients. However, no data are currently available on the effect of HDL on myocardial perfusion.

Methods and Results—

In this study, administration of human HDL enhanced incorporation of the perfusion tracer
99m
Tc-methoxyisobutylisonitrile (
99m
Tc-MIBI) into the murine heart in vivo by ≈18%. This increase was completely abolished in mice deficient for endothelial NO synthase. Because we have recently identified sphingosine 1-phosphate (S1P) as an important vasoactive component contained in HDL, we measured myocardial perfusion after administration of S1P in vivo. We observed an ≈25% decrease in myocardial MIBI uptake, which was abolished in mice deficient for the S1P receptor S1P
3
. In

S1P
3
−/−

mice, the stimulatory effect of HDL on myocardial perfusion was preserved.

Conclusions—

HDL increased myocardial perfusion under basal conditions in vivo via NO-dependent mechanisms, whereas S1P inhibited myocardial perfusion through the S1P
3
receptor. Thus, HDL may reduce coronary risk via direct NO-mediated vasodilatory effects on the coronary circulation.
Overexpression of Brain Natriuretic Peptide Facilitates Neutrophil Infiltration and Cardiac Matrix Metalloproteinase-9 Expression After Acute Myocardial Infarction
Authors: Kawakami Rika , Saito Yoshihiko , Kishimoto Ichiro , Harada Masaki , Kuwahara Koichiro , Takahashi Nobuki , Nakagawa Yasuaki , Nakanishi Michio , Tanimoto Keiji , Usami Satoru , Yasuno Shinji , Kinoshita Hideyuki , Chusho Hideki , Tamura Naohisa , Ogawa Yoshihiro , Nakao Kazuwa
Published: November 2004

Background—

Recent clinical trials have shown that systemic infusion of nesiritide, a recombinant human brain natriuretic peptide (BNP), improves hemodynamic parameters in acutely decompensated hearts. This suggests that BNP exerts a direct cardioprotective effect and might thus be a useful therapeutic agent with which to treat acute myocardial infarction (MI). In the present study, we used BNP-transgenic (BNP-Tg) mice with elevated plasma BNP to determine whether and how BNP contributes to left ventricular remodeling and healing after MI.

Methods and Results—

We examined the accumulation of neutrophils and the expression and activation of matrix metalloproteinase (MMP)-9 in the ventricles of male BNP-Tg mice and their nontransgenic (non-Tg) littermates during the early phase after acute MI. The numbers of neutrophils infiltrating the infarcted area were significantly increased in BNP-Tg mice 3 days after MI. In addition, both the gene expression and zymographic activity of MMP-9, but not MMP-2, were significantly higher in BNP-Tg than non-Tg mice. Double immunostaining revealed that neutrophils are the main source of the MMP-9, although doxycycline, an MMP inhibitor, had no effect on neutrophil infiltration of the infarcted area in BNP-Tg mice.

Conclusions—

These results demonstrate that elevated plasma BNP facilitates neutrophil infiltration of the infarcted area after MI and increases the activity of the MMP-9 they produce. This suggests that BNP plays a key role in the processes of extracellular matrix remodeling and wound-healing during the early phase after acute MI.
Cardiovascular, Renal, and Metabolic Responses to Chronic Central Administration of Agouti-Related Peptide
Authors: Tallam Lakshmi S. , Kuo Jay J. , da Silva Alexandre A. , Hall John E.
Published: November 2004

Although excess hypothalamic agouti-related peptide (AGRP), an endogenous antagonist of the melanocortin 3/4 receptor, causes hyperphagia and obesity, its role in regulating cardiovascular function is unclear. This study examined control of mean arterial pressure (MAP), heart rate (HR), and metabolism during chronic central administration of AGRP in rats. A cannula was placed in the lateral ventricle for intracerebroventricular infusion, and arterial and venous catheters were implanted for monitoring MAP and HR 24 hours per day, as well as intravenous infusions. After a 5-day control period, rats received AGRP (n=6; 0.02 nmol per hour ICV) or artificial cerebrospinal fluid (aCSF; n=9; 0.02 nmol per hour ICV) for 12 days, followed by a 5-day recovery period. A third group was infused intracerebroventricularly with AGRP and pair-fed to match food intake of control rats (n=7). AGRP produced a peak decrease in MAP and HR of −7±2 mm Hg and −68±7 bpm, respectively, despite increased food intake (from 23±0.5 to 36±3 g per day) and weight gain (from 350±8 to 454±5 g). AGRP also increased glomerular filtration rate, plasma insulin, glucose, and leptin. AGRP infusion in pair-fed rats produced a peak decrease in HR of −70±8 bpm but did not alter MAP or other variables. The metabolic effects of AGRP may be secondary to hyperphagia because they were abolished in pair-fed rats. aCSF infusion did not change any of the variables studied. These results demonstrate that increased central nervous system AGRP levels produce chronic reductions in MAP and HR despite marked increases in food intake and weight gain that normally tend to raise arterial pressure.
Novel Approach to Examining First Cardiovascular Events After Hypertension Onset
Authors: Lloyd-Jones Donald M. , Leip Eric P. , Larson Martin G. , Vasan Ramachandran S. , Levy Daniel
Published: November 2004

Hypertension confers risk for multiple types of cardiovascular events, but competing risks for these outcomes are unknown. We estimated the competing risks over 12 years after hypertension onset among cases and age-, sex-, and examination-matched controls using competing Cox cumulative incidence and proportional hazards models. We included all Framingham Heart Study subjects examined after 1977 with new-onset hypertension who were free of cardiovascular disease. There were 645 men and 702 women with new-onset hypertension (mean age: men, 55±12 years; women, 59±12 years). Compared with matched nonhypertensive controls, subjects with new-onset hypertension were more likely to experience a cardiovascular event first rather than noncardiovascular death. Among new-onset hypertensives, the 12-year competing cumulative incidence of any cardiovascular end point as a first event in men was 24.7%, compared with 9.8% for noncardiovascular death (hazards ratio [HR], 2.53; 95% confidence interval [CI], 1.83 to 3.50); in women, the competing incidences were 16.0% versus 10.1%, respectively (HR, 1.58; 95% CI, 1.13 to 2.20). The most common first major cardiovascular events were hard coronary disease (8.2%) in men and stroke (5.2%) in women. Type and incidence of first cardiovascular events varied by age and severity of hypertension at onset, with stroke predominating among older subjects with new-onset hypertension. After hypertension onset, cardiovascular events are more likely to occur first as opposed to noncardiovascular death. Types of initial events differ by gender, age, and severity of hypertension at onset. These results represent a novel approach to understanding the complications of hypertension and may help target therapies for patients with new-onset hypertension to optimize prevention strategies.
Role of Podocytes for Reversal of Glomerulosclerosis and Proteinuria in the Aging Kidney After Endothelin Inhibition
Authors: Ortmann Jana , Amann Kerstin , Brandes Ralf P. , Kretzler Matthias , Münter Klaus , Parekh Niranjan , Traupe Tobias , Lange Melanie , Lattmann Thomas , Barton Matthias
Published: November 2004

The cause of focal-segmental glomerulosclerosis as a consequence of physiological aging, which is believed to be inexorable, is unknown. This study investigated whether inhibition of endothelin-1, a growth-promoting peptide contributing to renal injury in hypertension and diabetes, affects established glomerulosclerosis and proteinuria in the aged kidney. We also determined the role of endothelin receptors for podocyte injury in vivo and in vitro. Aged Wistar rats, a model of spontaneous age-dependent glomerulosclerosis, were treated with the orally active endothelin subtype A (ET
A
) receptor antagonist darusentan, and evaluation of renal histology, renal function studies, and expression analyses were performed. In vitro experiments using puromycin aminonucleoside to induce podocyte injury investigated the role of ET
A
receptor signaling for apoptosis, cytoskeletal injury, and DNA synthesis. In aged Wistar rats, established glomerulosclerosis and proteinuria were reduced by >50% after 4 weeks of darusentan treatment, whereas blood pressure, glomerular filtration rate, or tubulo-interstitial renal injury remained unaffected. Improvement of structural injury in glomeruli and podocytes was accompanied by a reduction of the expression of matrix metalloproteinase-9 and p21
Cip1/WAF1
. In vitro experiments blocking ET
A
receptors using specific antagonists or RNA interference prevented apoptosis and structural damage to podocytes induced by puromycin aminonucleoside. In conclusion, these results support the hypothesis that endogenous endothelin contributes to glomerulosclerosis and proteinuria in the aging kidney. The results further suggest that age-dependent glomerulosclerosis is not merely a “degenerative” but a reversible process locally confined to the glomerulus involving recovery of podocytes from previous injury.
Transcriptional Regulation of Renin
Authors: Pan Li , Gross Kenneth W.
Published: November 2004

Renin, as a component of the renin-angiotensin system, plays important roles in the regulation of blood pressure, electrolyte homeostasis, and mammalian renal development. Transcription of renin genes is subject to complex developmental and tissue-specific regulation. Progress has been made recently in elucidating the molecular mechanisms involved in renin gene expression. Using mouse As4.1 cells, which have many features characteristic of the renin-expressing juxtaglomerular cells of kidney, a proximal promoter region (−197 to −50 bp) and an enhancer (−2866 to −2625 bp) have been identified in the mouse renin gene,

Ren-1
c

, that are critical for its expression. The proximal promoter region contains at least 7 transcription factor-binding sites, including a binding site for the products of
Hox
, developmental control genes. The enhancer consists of at least 11 transcription factor-binding sites and is responsive to various signal transduction pathways, including cAMP, retinoic acid, endothelin-1, and cytokines, to alter renin mRNA levels. Sequence highly homologous to the mouse enhancer is also found in the human and rat renin genes. How these regulatory regions function in vivo will be the focus of future study.
Comparing Ordinary Craft Production: Textile and Pottery Production in Roman Asia Minor
Authors: Poblome Jeroen
Published: November 2004

I present in this paper a framework of description for pottery and textile manufacturing in Roman Asia Minor. The research forms part of a wider debate on the speci fic, but generally underestimated contribution of the production of artisans to the ancient economy. The regulatory factors and production organisation of both crafts are remarkably similar and are placed against the agricultural background of a pre-industrial society.
Tensile Properties of Unsaturated Polyester-Based Sisal Fiber–Glass Fiber Hybrid Composites
Authors: John K. , Naidu S. Venkata
Published: November 2004

The variation of tensile strength of unsaturated polyester based sisal–glass hybrid composites with fiber loading has been studied. The tensile strength of these hybrid composites has been found to be higher than that of the matrix. The effects of NaOH treatment and trimethoxy silane (coupling agent) treatment on the tensile properties of these sisal–glass hybrid composites have also been studied. Significant improvement in tensile strength of the sisal–glass hybrid composites has been observed by these treatments.
‘To What Purpose Does It Think?’: Dreams, Sick Bodies and Confused Minds in the Age of Reason
Authors: Dacome Lucia
Published: November 2004

This paper investigates the debate on the nature of dreams that took place in eighteenth-century Britain. Focusing on the increasingly popular view of the time that perfect sleep was sleep without dreams, it examines the medicalization of dreaming that developed alongside the conceptualization of dreams as instances of mental derangement. At the end of the seventeenth century, John Locke had likened dreaming to madness and drunkenness, and characterized it as a disturbance of the self. In the course of the eighteenth century, physicians, religious preachers, champions of politeness and moral philosophers all provided competing accounts of the doubling of consciousness which was incidental to dreaming. This paper situates their attempts in the context of a re-assessment of the authorities that defined what constituted credible and reliable thinking. It does so by drawing attention to the body as one of the crucial sites in which changing attitudes towards dreaming were discussed and negotiated.
The Sin in the Aetiological Concept of Johann Christian August Heinroth (1773–1843).
Authors: Steinberg Holger
Published: November 2004

Throughout his work Johann Christian August Heinroth regarded sin to be the cause of mental illness. The present two-part paper investigates what exactly Heinroth understood by sin. Based on a thorough analysis of his own texts, this study shows that on the one hand Heinroth referred to sin in a Christian-Protestant sense. On the other, however, a moral-ethical code of conduct was also involved. Thus, Heinroth did not regard sin as a singular event, but rather as a life conducted in a wrong way for years or even decades, by which he meant a steady striving towards earthly, bodily satisfaction.
The Outbreak of Mass Allegations of Satanist Child Abuse in the Parish of Rättvik, Sweden, 1670–71: Two Texts by Gustav J. Elvius
Authors: SjöBerg Rickard L.
Published: November 2004

During recent decades, interpretation of mass allegations of Satanist child abductions have challenged psychiatrists and mental health professionals in the Western world. It has been argued that a useful perspective on this phenomenon may be gained from a study of historical parallels from countries such as Spain, Germany and Sweden. The texts translated below are an eyewitness account of the witch panic in Rättvik 1670–71 and a letter of 1671, both written by the Reverend Gustav Elvius.
Reconstituting the Global Public Domain — Issues, Actors, and Practices
Authors: Ruggie John Gerard
Published: November 2004

This article draws attention to a fundamental reconstitution of the global public domain — away from one that for more than three centuries equated the ‘public’ in international politics with sovereign states and the interstate realm to one in which the very system of states is becoming embedded in a broader and deepening transnational arena concerned with the production of global public goods. One concrete instance of this transformation is the growing significance of global corporate social responsibility initiatives triggered by the dynamic interplay between civil society actors and multinational corporations. The UN Global Compact and corporate involvement in HIV/AIDS treatment programs are discussed as examples. The analytical parameters of the emerging global public domain are defined and some of its consequences illustrated by the chain of responses to the Bush Administration’s rejection of the Kyoto Protocol by a variety of domestic and transnational social actors.
The Problem with Party Finance
Authors: Hopkin Jonathan
Published: November 2004

This article presents some theoretical contours for the study of party finance and its consequences. Two broad issues are explored. First, the article develops an account of changes in patterns of party finance, and in particular the move away from the ‘mass party’ model of funding towards ‘elite party’ and ‘cartel party’ models. Party finance is conceptualized as a collective action problem, and four ‘post-mass party’ financial strategies are identified. Second, the article addresses normative issues, assessing how these four financial models perform in terms of ‘liberal’ and ‘populist’ theories of democracy. It is concluded that the mass party model remains closest to the ‘democratic’ ideal, while the state-financed (‘cartel’) model is a reasonable pragmatic response to the decline in party membership.